summaryrefslogtreecommitdiffstats
path: root/rbutil/mkzenboot/mkzenboot.c
blob: 932da771bfbac054371c3184a3d77cb1ca74890e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
/***************************************************************************
 *             __________               __   ___.
 *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
 *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
 *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
 *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
 *                     \/            \/     \/    \/            \/
 * $Id$
 *
 * Copyright (C) 2008 by Maurus Cuelenaere
 * Based on zenutils by Rasmus Ry <rasmus.ry{at}gmail.com>
 * Copyright (C) 2013 by Amaury Pouly
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
 * KIND, either express or implied.
 *
 ****************************************************************************/
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include "mkzenboot.h"
#include "utils.h"
#include "dualboot.h"

/**
 * Keys used by players
 */
static const char null_key_v1[]  = "CTL:N0MAD|PDE0.SIGN.";
static const char null_key_v2[]  = "CTL:N0MAD|PDE0.DPMP.";
static const char null_key_v3[]  = "CTL:N0MAD|PDE0.DPFP.";
static const char null_key_v4[]  = "CTL:Z3N07|PDE0.DPMP.";

static const char tl_zvm_key[]   = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen Vision:M";
static const char tl_zvm60_key[] = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen Vision:M (D"
                                   "VP-HD0004)";
static const char tl_zen_key[]   = "1sN0TM3D az u~may th1nk*"
                                   "Creative ZEN";
static const char tl_zenxf_key[] = "1sN0TM3D az u~may th1nk*"
                                   "Creative ZEN X-Fi";
static const char tl_zenmo_key[] = "1sN0TM3D az u~may th1nk*"
                                   "Creative ZEN Mozaic";
static const char tl_zv_key[]    = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen Vision";
static const char tl_zvw_key[]   = "1sN0TM3D az u~may th1nk*"
                                   "Creative ZEN Vision W";
static const char tl_zm_key[]    = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen Micro";
static const char tl_zmp_key[]   = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen MicroPhoto";
static const char tl_zs_key[]    = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen Sleek";
static const char tl_zsp_key[]   = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen Sleek Photo";
static const char tl_zt_key[]    = "1sN0TM3D az u~may th1nk*"
                                   "Creative Zen Touch";
static const char tl_zx_key[]    = "1sN0TM3D az u~may th1nk*"
                                   "NOMAD Jukebox Zen Xtra";
static const char tl_zenv_key[]  = "1sN0TM3D az u~may th1nk*"
                                   "Creative ZEN V";
static const char tl_zenvp_key[] = "1sN0TM3D az u~may th1nk*"
                                   "Creative ZEN V Plus";
static const char tl_zenvv_key[] = "1sN0TM3D az u~may th1nk*"
                                   "Creative ZEN V (Video)";

struct player_info_t
{
    const char* name;
    const char* null_key;  /* HMAC-SHA1 key */
    const char* tl_key;    /* BlowFish key */
    bool big_endian;
    char *cinf;
};

static struct player_info_t zen_players[] =
{
    {"Zen Vision:M", null_key_v2, tl_zvm_key, false, NULL},
    {"Zen Vision:M 60GB", null_key_v2, tl_zvm60_key, false, NULL},
    {"Zen", null_key_v4, tl_zen_key, false, "Creative ZEN"},
    {"Zen X-Fi", null_key_v4, tl_zenxf_key, false, "Creative ZEN X-Fi"},
    {"Zen Mozaic", null_key_v4, tl_zenmo_key, false, "Creative ZEN Mozaic"},
    {"Zen Vision", null_key_v2, tl_zv_key, false, NULL},
    {"Zen Vision W", null_key_v2, tl_zvw_key, false, NULL},
    {"Zen Micro", null_key_v1, tl_zm_key, true, NULL},
    {"Zen MicroPhoto", null_key_v1, tl_zmp_key, true, NULL},
    {"Zen Sleek", null_key_v1, tl_zs_key, true, NULL},
    {"Zen SleekPhoto", null_key_v1, tl_zsp_key, true, NULL},
    {"Zen Touch", null_key_v1, tl_zt_key, true, NULL},
    {"Zen Xtra", null_key_v1, tl_zx_key, true, NULL},
    {"Zen V", null_key_v3, tl_zenv_key, false, "Creative ZEN V"},
    {"Zen V Plus", null_key_v3, tl_zenvp_key, false, NULL},
    {"Zen V Video", null_key_v3, tl_zenvv_key, false, NULL},
    {NULL, NULL, NULL, false, NULL}
};

/**
 * Information on how to patch firmwares
 */
struct zen_model_desc_t
{
    /* Descriptive name of this model (must match player in zen_players[]) */
    const char *model_name;
    /* Model name used in the Rockbox header in ".zen" files - these match the
       -add parameter to the "scramble" tool */
    const char *rb_model_name;
    /* Model number used to initialise the checksum in the Rockbox header in
       ".zen" files - these are the same as MODEL_NUMBER in config-target.h */
    const int rb_model_num;
    /* Bootloader load address */
    uint32_t bootloader_addr;
    /* Dualboot code for this model */
    const unsigned char *dualboot;
    /* Size of dualboot functions for this model */
    int dualboot_size;
};

/* keep this consistent with the address in dualboot.lds */
static const struct zen_model_desc_t zen_models[] =
{
    [MODEL_UNKNOWN] =
    {
        "Unknown", "    ", 0, 0, NULL, 0
    },
    [MODEL_ZENV] =
    {
        "Zen V", "zenv", 92, 0x61000000, dualboot_zenv, sizeof(dualboot_zenv)
    },
    [MODEL_ZENXFI] =
    {
        "Zen X-Fi", "zxfi", 86, 0x41000000, dualboot_zenxfi, sizeof(dualboot_zenxfi)
    },
    [MODEL_ZENMOZAIC] =
    {
        "Zen Mozaic", "zmoz", 87, 0x41000000, dualboot_zenmozaic, sizeof(dualboot_zenmozaic)
    },
    [MODEL_ZEN] =
    {
        "Zen", "zen", 90, 0x41000000, dualboot_zen, sizeof(dualboot_zen)
    },
};

/**
 * MD5 knowledge base
 */

struct zen_md5sum_t
{
    /* Device model */
    enum zen_model_t model;
    /* md5sum of the file */
    char *md5sum;
    /* Version string */
    const char *version;
};

static const struct zen_md5sum_t zen_sums[] =
{
    /** Zen Mozaic */
    {
        /* Version 1.06.01e */
        MODEL_ZENMOZAIC, "88a856f8273b2bc3fcacf1f067a44aa8", "1.06.01e"
    },
    /** Zen X-Fi */
    {
        /* Version 1.04.08e */
        MODEL_ZENXFI, "f07e2e75069289a2aa14c6583bd9643b", "1.04.08e"
    },
    {
        /* Version 1.04.08 */
        MODEL_ZENXFI, "c3cddf8468d8c8982e93aa9986c5a152", "1.04.08"
    },
    /** Zen V */
    {
        /* Version 1.32.01e */
        MODEL_ZENV, "2f6d3e619557583c30132ac87221bc3e", "1.32.01e"
    },
    /** Zen */
    {
        /* Version 1.21.03e */
        MODEL_ZEN, "1fe28f587f87ac3c280281db28c42465", "1.21.03e"
    }
};

#define NR_ZEN_PLAYERS  (sizeof(zen_players) / sizeof(zen_players[0]))
#define NR_ZEN_SUMS     (sizeof(zen_sums) / sizeof(zen_sums[0]))
#define NR_ZEN_MODELS   (sizeof(zen_models) / sizeof(zen_models[0]))

#define MAGIC_ROCK      0x726f636b /* 'rock' */
#define MAGIC_RECOVERY  0xfee1dead
#define MAGIC_NORMAL    0xcafebabe

/**
 * Stolen from various places in our codebase
 */

/**
 * EDOC file format
 */
struct edoc_header_t
{
    char magic[4];
    uint32_t total_size;
    uint32_t zero;
};

struct edoc_section_header_t
{
    uint32_t addr;
    uint32_t size;
    uint32_t checksum;
};

uint32_t edoc_checksum(void *buffer, size_t size)
{
    uint32_t c = 0;
    uint32_t *p = buffer;
    while(size >= 4)
    {
        c += *p + (*p >> 16);
        p++;
        size -= 4;
    }
    if(size != 0)
        printf("[WARN] EDOC Checksum section size is not a multiple of 4 bytes, result is undefined!\n");
    return c & 0xffff;
}

#define errorf(err, ...) do { printf(__VA_ARGS__); return err; } while(0)

/**
 * How does patching code work
 * ---------------------------
 *
 * All Creative firmwares work the same: they start at 0 and the code sequence at
 * 0 always contains the vector table with ldr with offsets:
 *   0:       e59ff018        ldr     pc, [pc, #24]   ; 0x20
 *   4:       e59ff018        ldr     pc, [pc, #24]   ; 0x24
 *   8:       e59ff018        ldr     pc, [pc, #24]   ; 0x28
 *   c:       e59ff018        ldr     pc, [pc, #24]   ; 0x2c
 *  10:       e59ff018        ldr     pc, [pc, #24]   ; 0x30
 *  14:       e59ff018        ldr     pc, [pc, #24]   ; 0x34
 *  18:       e59ff018        ldr     pc, [pc, #24]   ; 0x38
 *  1c:       e59ff018        ldr     pc, [pc, #24]   ; 0x3c
 *  20:       0000dbd4        .word start
 *  24:       0000dcac        .word undef_instr_handler
 *  28:       0000dcb0        .word software_int_handler
 *  2c:       0000dcb4        .word prefetch_abort_handler
 *  30:       0000dcb8        .word data_abort_handler
 *  34:       0000dcbc        .word reserved_handler
 *  38:       0000dcc0        .word irq_handler
 *  3c:       0000dd08        .word fiq_handler
 *
 * To build a dual-boot image, we modify the start address to point to some
 * code we added to the image. Specifically we first add the stub, then
 * the rockbox image. We also write the old start address to this
 * stub so that it can either decide to run rockbox or patch back the
 * start address and jump to 0.
 * Singleboot and recovery is handled the same way except that both targets use
 * the same address and we drop the OF, so we create a fake vector table!
 */

struct dualboot_footer_t
{
    uint32_t magic;
    uint32_t of_addr;
    uint32_t rb_addr;
    uint32_t boot_arg;
} __attribute__((packed));

#define FOOTER_MAGIC    0x1ceb00da

static enum zen_error_t create_fake_image(uint8_t **fw, uint32_t *fw_size)
{
    /** We need to create a fake EDOC image, so first a header and one section
     * header with one data chunk. */
    /** The fake image is as follows:
     *   0:       e59ff018        ldr     pc, [pc, #24]   ; 0x20
     *   4:       e59ff018        ldr     pc, [pc, #24]   ; 0x24
     *   8:       e59ff018        ldr     pc, [pc, #24]   ; 0x28
     *   c:       e59ff018        ldr     pc, [pc, #24]   ; 0x2c
     *  10:       e59ff018        ldr     pc, [pc, #24]   ; 0x30
     *  14:       e59ff018        ldr     pc, [pc, #24]   ; 0x34
     *  18:       e59ff018        ldr     pc, [pc, #24]   ; 0x38
     *  1c:       e59ff018        ldr     pc, [pc, #24]   ; 0x3c
     *  20:       00000040        .word   hang
     *  24:       00000040        .word   hang
     *  28:       00000040        .word   hang
     *  2c:       00000040        .word   hang
     *  30:       00000040        .word   hang
     *  34:       00000040        .word   hang
     *  38:       00000040        .word   hang
     *  3c:       00000040        .word   hang
     *  40 <hang>:
     *  40:       eafffffe        b       40 <hang> */
    *fw_size = sizeof(struct edoc_header_t) + sizeof(struct edoc_section_header_t) + 0x44;
    *fw = malloc(*fw_size);
    if(*fw == NULL)
        errorf(ZEN_ERROR, "[ERR] Allocation failed");
    struct edoc_header_t *hdr = (void *)*fw;
    memcpy(hdr->magic, "EDOC", 4);
    hdr->total_size = *fw_size - sizeof(struct edoc_header_t) + 4;
    hdr->zero = 0;
    struct edoc_section_header_t *sec = (void *)(hdr + 1);
    sec->addr = 0;
    sec->size = 0x44;
    uint32_t *p = (void *)(sec + 1);
    p[0] = p[1] = p[2] = p[3] = p[4] = p[5] = p[6] = p[7] = 0xe59ff018;
    p[8] = p[9] = p[10] = p[11] = p[12] = p[13] = p[14] = p[15] = 0x40;
    p[16] = 0xeafffffe;
    sec->checksum = edoc_checksum(p, 0x44);
    return ZEN_SUCCESS;
}

static enum zen_error_t patch_firmware(uint8_t **fw, uint32_t *fw_size,
    void *boot, size_t boot_size, struct zen_option_t opt)
{
    /* check if dualboot stub is available */
    const void *dualboot = zen_models[opt.model].dualboot;
    int dualboot_size = zen_models[opt.model].dualboot_size;
    uint32_t dualboot_addr = zen_models[opt.model].bootloader_addr;
    if(dualboot == NULL)
        errorf(ZEN_DONT_KNOW_HOW_TO_PATCH, "[ERR] I don't have a dualboot stub for this model\n");
    /* if not asked to dualboot, drop OF and create a fake image */
    if(opt.output != ZEN_DUALBOOT)
    {
        enum zen_error_t ret = create_fake_image(fw, fw_size);
        if(ret != ZEN_SUCCESS)
            return ret;
    }
    /* compute final image size: add stub + bootloader in one block as a section */
    int extra_size = sizeof(struct edoc_section_header_t) + dualboot_size + boot_size;
    *fw_size += extra_size;
    *fw = realloc(*fw, *fw_size);
    if(*fw == NULL)
        errorf(ZEN_ERROR, "[ERR] Allocation failed");
    /* sanity check */
    struct edoc_header_t *hdr = (void *)*fw;
    if(memcmp(hdr->magic, "EDOC", 4) != 0)
        errorf(ZEN_FW_INVALID, "[ERR] Firmware doesn't use EDOC format\n");
    /* validate image and find OF start addr */
    uint32_t of_addr = 0;
    struct edoc_section_header_t *sec_hdr = (void *)(hdr + 1);
    while((void *)sec_hdr - (void *)&hdr->zero < hdr->total_size)
    {
        if(sec_hdr->checksum != edoc_checksum(sec_hdr + 1, sec_hdr->size))
            errorf(ZEN_FW_INVALID, "[ERR] Firmware checksum error\n");
        if(sec_hdr->addr == 0)
        {
            uint32_t *start_vector = ((void *)(sec_hdr + 1) + 0x20);
            /* extract address */
            of_addr = *(uint32_t *)start_vector;
            /* patch vector */
            *start_vector = dualboot_addr;
            /* fix checksum */
            sec_hdr->checksum = edoc_checksum(sec_hdr + 1, sec_hdr->size);
        }
        sec_hdr = (void *)(sec_hdr + 1) + sec_hdr->size;
    }
    if(of_addr == 0)
        errorf(ZEN_FW_INVALID, "[ERR] Firmware doesn't have the expected format\n");
    printf("[INFO] OF start address: %#x\n", of_addr);
    /* add extra section */
    sec_hdr->addr = dualboot_addr;
    sec_hdr->size = dualboot_size + boot_size;
    /* add extra data */
    memcpy(sec_hdr + 1, dualboot, dualboot_size);
    memcpy((void *)(sec_hdr + 1) + dualboot_size, boot, boot_size);
    /* locate and patch dualboot footer */
    struct dualboot_footer_t *footer = (void *)(sec_hdr + 1) + dualboot_size -
        sizeof(struct dualboot_footer_t);
    if(footer->magic != FOOTER_MAGIC)
        errorf(ZEN_FW_INVALID, "[ERR] Footer magic mismatch\n");
    uint32_t rb_addr = dualboot_addr + dualboot_size;
    printf("[INFO] RB start address: %#x\n", rb_addr);
    footer->of_addr = opt.output == ZEN_DUALBOOT ? of_addr : rb_addr;
    footer->rb_addr = rb_addr;
    footer->boot_arg = opt.output == ZEN_RECOVERY ? 0xfee1dead : 0xcafebabe;
    printf("[INFO] Footer: 0x%08x 0x%08x 0x%08x\n", footer->of_addr, footer->rb_addr,
        footer->boot_arg);
    /* fix image */
    sec_hdr->checksum = edoc_checksum(sec_hdr + 1, sec_hdr->size);
    hdr->total_size += extra_size;
    return ZEN_SUCCESS;
}

struct player_info_t *get_player_info(enum zen_model_t model)
{
    for(int i = 0; zen_players[i].name; i++)
        if(strcmp(zen_models[model].model_name, zen_players[i].name) == 0)
            return &zen_players[i];
    return NULL;
}

enum zen_error_t build_firmware(void *exec, size_t exec_size, void *boot, size_t boot_size,
    const char *outfile, struct zen_option_t opt)
{
    uint8_t *buffer = exec;
    /** find player info */
    struct player_info_t *player = get_player_info(opt.model);
    if(player == NULL)
        errorf(ZEN_UNSUPPORTED, "[ERR] There is no player info for this model\n");
    if(player->big_endian)
        errorf(ZEN_UNSUPPORTED, "[ERR] Big-endian players are currently unsupported\n");

    /** Find Win32 PE .data section */
    uint32_t data_ptr;
    uint32_t data_size;
    enum zen_error_t err = find_pe_data(exec, exec_size, &data_ptr, &data_size);
    if(err != ZEN_SUCCESS)
        errorf(err, "[ERR] Cannot find .data section\n");
    printf("[INFO] .data section is at 0x%x with size 0x%x\n", data_ptr, data_size);

    /** look for firmware and key in data section */
    uint32_t fw_offset = find_firmware_offset(&buffer[data_ptr], data_size);
    if(fw_offset == 0)
        errorf(ZEN_FW_INVALID, "[ERR] Couldn't find firmware offset\n");
    uint32_t fw_size = le2int(&buffer[data_ptr + fw_offset]);
    printf("[INFO] Firmware offset is at 0x%x with size 0x%x\n", data_ptr + fw_offset, fw_size);
    const char *fw_key = find_firmware_key(exec, exec_size);
    if(fw_key == NULL)
        errorf(ZEN_FW_INVALID, "[ERR] Couldn't find firmware key\n");
    printf("[INFO] Firmware key is %s\n", fw_key);

    /** descramble firmware */
    printf("[INFO] Descrambling firmware... ");
    if(!crypt_firmware(fw_key, &buffer[data_ptr + fw_offset + 4], fw_size))
        errorf(ZEN_ERROR, "Fail!\n");
    else
        printf("Done!\n");
    /** decompress it */
    uint8_t *out_buffer = malloc(fw_size * 2);
    if(out_buffer == NULL)
        errorf(ZEN_ERROR, "[ERR] Couldn't allocate memory");
    memset(out_buffer, 0, fw_size * 2);
    printf("[INFO] Decompressing firmware... ");
    char *err_msg;
    if(!inflate_to_buffer(&buffer[data_ptr + fw_offset + 4], fw_size, out_buffer,
            fw_size * 2, &err_msg))
        errorf(ZEN_ERROR, "Fail!\n[ERR] ZLib error: %s\n", err_msg);
    else
        printf("Done!\n");

    /** check format and resize the buffer */
    if(memcmp(out_buffer, "FFIC", 4) != 0)
        errorf(ZEN_FW_INVALID, "[ERR] CIFF header doesn't match\n");
    uint32_t ciff_size = le2int(&out_buffer[4]) + 8 + 28; /* CIFF block + NULL block*/
    printf("[INFO] Total firmware size: %d\n", ciff_size);
    out_buffer = realloc(out_buffer, ciff_size);
    if(out_buffer == NULL)
        errorf(ZEN_ERROR, "[ERR] Cannot resize memory block\n");

    /** look for firmware file */
    printf("[INFO] Locating encoded block... ");
    uint32_t fw_off = 8;
    uint8_t *cinf_ptr = NULL;
    while(memcmp(&out_buffer[fw_off], " LT\xa9", 4) != 0 && fw_off < ciff_size)
    {
        if(memcmp(&out_buffer[fw_off], "FNIC", 4) == 0)
        {
            cinf_ptr = &out_buffer[fw_off + 8];
            fw_off += 4 + 4 + 96;
        }
        else if(memcmp(&out_buffer[fw_off], "ATAD", 4) == 0)
        {
            fw_off += 4;
            fw_off += le2int(&out_buffer[fw_off]);
            fw_off += 4;
        }
        else
            errorf(ZEN_FW_INVALID, "Fail!\n[ERR] Unknown block\n");
    }
    if(fw_off >= ciff_size || memcmp(&out_buffer[fw_off], " LT\xa9", 4) != 0)
        errorf(ZEN_FW_INVALID, "Fail!\n[ERR] Couldn't find encoded block\n");
    if(!cinf_ptr)
        errorf(ZEN_FW_INVALID, "Fail!\n[ERR] Couldn't find CINF\n");
    printf("Done!\n");

    /** validate player if possible */
    printf("[INFO] Checking player model...");
    if(player->cinf)
    {
        char cinf_ascii[96];
        for(int j = 0; j < 96; j++)
            cinf_ascii[j] = *(unsigned short *)&cinf_ptr[2 * j];
        if(strncmp(cinf_ascii, player->cinf, 96) != 0)
            errorf(ZEN_FW_MISMATCH, "Fail!\n[ERR] Player mismatch: CINF indicates '%s' instead of '%s'\n",
                cinf_ascii, player->cinf);
        else
            printf("Done!\n");
    }
    else
        printf("Bypass!\n");

    /** decrypt firmware */
    printf("[INFO] Decrypting encoded block... ");
    uint32_t iv[2];
    iv[0] = 0;
    iv[1] = swap(le2int(&out_buffer[fw_off + 4]));
    if(!bf_cbc_decrypt((unsigned char*)player->tl_key, strlen(player->tl_key) + 1,
            &out_buffer[fw_off + 8], le2int(&out_buffer[fw_off + 4]), (const unsigned char*)&iv))
        errorf(ZEN_ERROR, "Fail!\n[ERR] Couldn't decrypt encoded block\n");
    printf("Done!\n");

    /** sanity checks on firmware */
    uint32_t jrm_size = le2int(&out_buffer[fw_off + 8]);
    if(jrm_size > le2int(&out_buffer[fw_off + 4]) * 3)
        errorf(ZEN_FW_INVALID, "[ERR] Decrypted length of encoded block is unexpectedly large: 0x%08x\n", jrm_size);
    printf("[INFO] Firmware size: %d\n", jrm_size);
    uint8_t *jrm = malloc(jrm_size);
    if(jrm == NULL)
        errorf(ZEN_ERROR, "[ERR] Couldn't allocate memory\n");
    memset(buffer, 0, jrm_size);

    /** decompress firmware */
    printf("[INFO] Decompressing encoded block... ");
    if(!cenc_decode(&out_buffer[fw_off + 12], le2int(&out_buffer[fw_off + 4]) - 4, jrm, jrm_size))
        errorf(ZEN_ERROR, "Fail!\n[ERR] Couldn't decompress the encoded block\n");
    printf("Done!\n");

    /** Copy OF because patching might modify it */
    void *jrm_save = malloc(jrm_size);
    uint32_t jrm_save_size = jrm_size;
    if(jrm_save == NULL)
        errorf(ZEN_ERROR, "[ERR] Couldn't allocate memory");
    memcpy(jrm_save, jrm, jrm_size);

    /** Patch firmware */
    err = patch_firmware(&jrm, &jrm_size, boot, boot_size, opt);
    if(err != ZEN_SUCCESS)
        errorf(err, "[ERR] Couldn't patch firmware\n");

    /** Rebuild archive */
    bool keep_old_bits = opt.output == ZEN_DUALBOOT || opt.output == ZEN_MIXEDBOOT;
    bool keep_of = opt.output == ZEN_MIXEDBOOT;
    /* if we keep old stuff, keep everything up to LT block, otherwise just CIFF header */
    uint32_t off = keep_old_bits ? fw_off : 8;
    /* move the rest of the archive if keeping old stuff */
    if(keep_old_bits)
    {
        uint32_t copy_off = fw_off + 8 + le2int(&out_buffer[fw_off + 4]);
        uint32_t copy_size = ciff_size - fw_off - 8 - le2int(&out_buffer[fw_off + 4]) - 28;
        memmove(&out_buffer[off], &out_buffer[copy_off], copy_size);
        off += copy_size;
    }
    /* if we keep the OF, put a copy of it after renaming it to Hcreativeos.jrm */
    if(keep_of)
    {
        out_buffer = realloc(out_buffer, off + jrm_save_size + 40);
        if(out_buffer == NULL)
            errorf(ZEN_ERROR, "[ERR] Couldn't resize memory block\n");
        printf("[INFO] Renaming encoded block to Hcreativeos.jrm... ");
        memcpy(&out_buffer[off], "ATAD", 4);
        int2le(jrm_save_size + 32, &out_buffer[off + 4]);
        memset(&out_buffer[off + 8], 0, 32);
        memcpy(&out_buffer[off + 8], "H\0c\0r\0e\0a\0t\0i\0v\0e\0o\0s\0.\0j\0r\0m", 30);
        memcpy(&out_buffer[off + 40], jrm_save, jrm_save_size);
        off += jrm_save_size + 40;
        printf("Done!\n");
    }
    /* put modified firmware */
    out_buffer = realloc(out_buffer, off + jrm_size + 40);
    if(out_buffer == NULL)
        errorf(ZEN_ERROR, "[ERR] Couldn't resize memory block\n");
    printf("[INFO] Adding Hjukebox2.jrm... ");
    memcpy(&out_buffer[off], "ATAD", 4);
    int2le(jrm_size + 32, &out_buffer[off + 4]);
    memset(&out_buffer[off + 8], 0, 32);
    memcpy(&out_buffer[off + 8], "H\0j\0u\0k\0e\0b\0o\0x\0""2\0.\0j\0r\0m", 26);
    memcpy(&out_buffer[off + 40], jrm, jrm_size);
    off += jrm_size + 40;
    printf("Done!\n");

    /** fix header */
    int2le(off - 8, &out_buffer[4]);

    /** update checksum */
    printf("[INFO] Updating checksum... ");
    out_buffer = realloc(out_buffer, off + 28);
    if(out_buffer == NULL)
        errorf(ZEN_ERROR, "[ERR] Couldn't resize memory block\n");
    memcpy(&out_buffer[off], "LLUN", 4);
    int2le(20, &out_buffer[off + 4]);
    hmac_sha1((unsigned char*)player->null_key, strlen(player->null_key), out_buffer,
        off, &out_buffer[off + 8]);
    off += 28;
    printf("Done!\n");

    err = write_file(outfile, out_buffer, off);

    free(jrm);
    free(jrm_save);
    free(out_buffer);
    return err;
}

/* find an entry into zen_sums which matches the MD5 sum of a file */
static enum zen_error_t find_model_by_md5sum(uint8_t file_md5sum[16], int *md5_idx)
{
    int i = 0;
    while(i < NR_ZEN_SUMS)
    {
        uint8_t md5[20];
        if(strlen(zen_sums[i].md5sum) != 32)
            errorf(ZEN_ERROR, "[ERR][INTERNAL] Invalid MD5 sum in zen_sums\n");
        for(int j = 0; j < 16; j++)
        {
            uint8_t a, b;
            if(convxdigit(zen_sums[i].md5sum[2 * j], &a) || convxdigit(zen_sums[i].md5sum[2 * j + 1], &b))
                errorf(ZEN_ERROR, "[ERR][INTERNAL] Bad checksum format: %s\n", zen_sums[i].md5sum);
            md5[j] = (a << 4) | b;
        }
        if(memcmp(file_md5sum, md5, 16) == 0)
            break;
        i++;
    }
    if(i == NR_ZEN_SUMS)
        errorf(ZEN_NO_MATCH, "[ERR] MD5 sum doesn't match any known file\n");
    *md5_idx = i;
    return ZEN_SUCCESS;
}

enum zen_error_t mkzenboot(const char *infile, const char *bootfile,
    const char *outfile, struct zen_option_t opt)
{
    /* determine firmware model */
    void *fw;
    size_t fw_size;
    enum zen_error_t err = read_file(infile, &fw, &fw_size);
    uint8_t file_md5sum[16];
    err = compute_md5sum_buf(fw, fw_size, file_md5sum);
    if(err != ZEN_SUCCESS)
    {
        free(fw);
        return err;
    }
    printf("[INFO] MD5 sum of the file: ");
    for(int i = 0; i < 16; i++)
        printf("%02X ", file_md5sum[i]);
    printf("\n");
    if(opt.model == MODEL_UNKNOWN)
    {
        int idx;
        err = find_model_by_md5sum(file_md5sum, &idx);
        if(err != ZEN_SUCCESS)
        {
            free(fw);
            errorf(err, "[ERR] Cannot determine model type\n");
        }
        opt.model = zen_sums[idx].model;
        printf("[INFO] MD5 matches %s, version %s\n",
            zen_models[opt.model].model_name, zen_sums[idx].version);
    }
    printf("[INFO] Model is: %s\n", zen_models[opt.model].model_name);
    /* load rockbox file */
    uint8_t *boot;
    size_t boot_size;
    err = read_file(bootfile, (void **)&boot, &boot_size);
    if(err != ZEN_SUCCESS)
    {
        free(fw);
        errorf(err, "[ERR] Cannot read boot file\n");
    }
    /* validate checksum */
    if(memcmp(boot + 4, zen_models[opt.model].rb_model_name, 4) != 0)
    {
        free(fw);
        free(boot);
        errorf(ZEN_BOOT_MISMATCH, "[ERR] Boot model mismatch\n");
    }
    printf("[INFO] Bootloader file matches model\n");
    uint32_t sum = zen_models[opt.model].rb_model_num;
    for(int i = 8; i < boot_size; i++)
        sum += boot[i];
    if(sum != be2int(boot))
    {
        free(fw);
        free(boot);
        errorf(ZEN_BOOT_CHECKSUM_ERROR, "[ERR] Checksum mismatch\n");
    }
    printf("[INFO] Bootloader file checksum is correct\n");
    /* produce file */
    err = build_firmware(fw, fw_size, boot + 8, boot_size - 8, outfile, opt);
    free(boot);
    free(fw);
    return err;
}