Today @ma1co (https://github.com/ma1co/fwtool.py) released an update to his fwtool.py tool that allows you to extract gen4 firmwares. The tool only allows you to decrypt the firmware at the moment, but I am sure it will only be a matter of time till he updates it to encrypt as well.

The method below was discovered by @vitaliy_kiselev and can be found here: https://www.personal-view.com/faqs/sony-hack/languages

NOTE2: this method is not only untested, it will likely brick your camera. Proceed with caution.

Preparation (for macOS)

1. Download the full source fwtool.py from the link above
2. Download the actual firmware for your camera, in my case for the A7III it was (https://www.sony.co.uk/electronics/support/e-mount-body-ilce-7-series/ilce-7m3/downloads/00015677)
3. copy the .dat firmware file from the dmg to the fwtool root folder
4. sudo easy_install pip
5. sudo pip install pycrypto
6. sudo pip install pyyaml

note: if at any point you found any of these steps confusing or indirect, you should stop and not do this

Guide:

1. python fwtool.py unpack -f FirmwareData_ILCE7M3V210.dat -o out (this is on macOS Mojave, your OS might require something different)
2. cd out/firmware.tar_unpacked/0110_backup/SYSASTRA-DSLR/TI
3. Swap the files of your current language (I have J1, see below list section as a reference. note that there are now 2 ALLLANG files one with CX62200 and one with CX62201 choose the one that corresponds to your camera language) with the All Language file (just rename them)
4. cd out/firmware.tar_unpacked/0111_backup_sum
5. edit 'backup.sum' in your favorite text editor

6. Swap the checksums with what ever language you have with the CX62200_ALLLANG bin file checksum

   0,ae35017d,00113eba,000001a4,00000000,000003e8,root,root,-1,-1,SYSASTRA-DSLR/TI/CX62200_ALLLANG.bin, 0,782ddbc1,00113eba,000001a4,00000000,000003e8,root,root,-1,-1,SYSASTRA-DSLR/TI/CX62200_J1.bin,

   becomes

   0,782ddbc1,00113eba,000001a4,00000000,000003e8,root,root,-1,-1,SYSASTRA-DSLR/TI/CX62200_ALLLANG.bin, 0,ae35017d,00113eba,000001a4,00000000,000003e8,root,root,-1,-1,SYSASTRA-DSLR/TI/CX62200_J1.bin,

7. Wait till we have a way to encrypt it. I just cant thank ma1co enough for making this possible up to this level! you rock. I will update this guide with results once ma1co releases an update.

List:

• Region ALLLANG .. I mean you should know what this means otherwise you should not do this.
• Region J1(JPN) supports Japanese only
• Region U2, CA2, AU2 supports English, French, Chinese,
• Region CEE2 (CEE) supports English, French, German, Spanish, Italian, Portuguese, Dutch, Russia, Sweden, Danish. Norway, Finnish, Poland, Czech, Hungarian.
• Region CEE4 supports English, French, German, Spanish, Italian, Portuguese, Dutch, Russia, Sweden, Danish. Norway, Finnish, Poland, Czech, Hungarian.
• Region CEE5 supports English, French, German, Spanish, Italian, Portuguese, Dutch, Russia, Sweden, Danish. Norway, Finnish, Poland, Czech, Hungarian.
• Region CEH E32, HK1, JE3, TW6 supports English, Spanish, Portuguese, Chinese, Arabic, Thai, Korean, Persian.
• Region CN2 supports English, Spanish, Portuguese, Chinese, Arabic, Thai, Korean, Persian.
• Region KR2 supports English, Spanish, Portuguese, Chinese, Arabic, Thai, Korean, Persian.