Some WIP code to deal with img4 files in a decent manner.

Prereq: either libcompression or liblzfse; or build one in-tree (has precedence)
    git submodule init && git submodule update && make -C lzfse [CC="cross-cc"] [LD="cross-ld"]

Build:
    make [CC="cross-cc"] [LD="cross-ld"] [CORECRYPTO=1] [COMMONCRYPTO=1]
        COMMONCRYPTO=1	use Apple CommonCrypto instead of OpenSSL (Darwin-only)
        CORECRYPTO=1	use the included corecrypto sources (has precedence)

Examples:

./img4 \
    -i DeviceTree.n51ap.im4p \
    -o dtre.img4 \
    -M manifest.im4m \
    -N 0x1122334455667788 \
    -T rdtr

./img4 \
    -i kc_iPhone6,1_9.0_13A344.im4p \
    -o krnl.img4 \
    -k a6ff60f2fcf3cdcaaf735e1683418ff56828540cd92ac15f3144ed4dc9d5bcb34c01cc8154bc22c3658d82b6c439340b \
    -M manifest.im4m \
    -N 0x1122334455667788 \
    -P kc_iPhone6,1_9.0_13A344.bpatch \
    -D \
    -T rkrn

Patches for kc_iPhone6,1_9.0_13A344:

# AMFI
0x006AF484 0xF6 0xE0
0x006AF485 0x57 0x03
0x006AF486 0xBD 0x00
0x006AF487 0xA9 0x32
0x006AF488 0xF4 0xC0
0x006AF489 0x4F 0x03
0x006AF48A 0x01 0x5F
0x006AF48B 0xA9 0xD6

# MAC
0x004823CC 0x00 0x00
0x004823CD 0x05 0x00
0x004823CE 0x40 0x80
0x004823CF 0xF9 0x52
#0x00F5595C 0xB2 0x00
#0x00F5595D 0x3E 0x00
#0x00F5595E 0x00 0x80
#0x00F5595F 0x94 0x52

-xerub