Tools Some clues about JB fw5.12.2

[howtojb]

I want to JB my KOA1 fw5.12.2,serach and read some post in this forum, got info: that is impossible! But I did not give up

downloaded two "bin" files

update_KOA_5.7.4_initial.bin(from mobileread forums)
and
update_kindle_oasis_5.9.7.bin(from amazon official page)

tried to downgrade my KOA1 FW from 5.12.2 to 5.7.4 or 5.7.9,
of course it does not work, I copied "update_kindle_oasis_5.9.7.bin" to kindle, and : Home -> Menu -> Settings -> Menu -> Update, popup error say, "...update file is wrong...", system directly delete the file"update_kindle_oasis_5.9.7.bin", kindle won't start update process.

then I tried something else, copy "update_KOA_5.7.4_initial.bin" to kindle, do NOT unplug usb cable, directly press power button and hold for 20 sceonds, KOA1 reboot, popup info"...kindle is update...please wait....", after half a minute, popup "...update is not successful ...error code is 15..."

I did same process for "update_kindle_oasis_5.9.7.bin",my kindle try to update FW, but faild, "...error code is 12..."

what that mean: when user copy update "bin" file to kindle, and do not unplug usb cable, and press power button for 20 sceonds, hard reboot kindle, kindle will try to run the "bin" file, of cause the file can not pass some kinde pre-check,popup error code.

that means, in above process, kindle try to execute user "bin" file, maybe someone in this forum can customizes a "bin" file, tricks the fw5.12.2 system, bypasses the pre-check, JB kindle system？

[JSWolf]

I think you are out of luck with 5.12.2 on your KO1.

[ilovejedd]

Originally Posted by howtojb

then I tried something else, copy "update_KOA_5.7.4_initial.bin" to kindle, do NOT unplug usb cable, directly press power button and hold for 20 sceonds, KOA1 reboot, popup info"...kindle is update...please wait....", after half a minute, popup "...update is not successful ...error code is 15..."

I did same process for "update_kindle_oasis_5.9.7.bin",my kindle try to update FW, but faild, "...error code is 12..."

what that mean: when user copy update "bin" file to kindle, and do not unplug usb cable, and press power button for 20 sceonds, hard reboot kindle, kindle will try to run the "bin" file, of cause the file can not pass some kinde pre-check,popup error code.

that means, in above process, kindle try to execute user "bin" file, maybe someone in this forum can customizes a "bin" file, tricks the fw5.12.2 system, bypasses the pre-check, JB kindle system？

This used to work on 5.6.x but they already plugged that hole.

If we can create a custom "bin" file that can pass or bypass the validation check, I expect it will work with the regular UYK menu option as well. The problem is how to create that bin file in the first place without knowing Amazon's private key.

[howtojb]

Originally Posted by ilovejedd

This used to work on 5.6.x but they already plugged that hole.

If we can create a custom "bin" file that can pass or bypass the validation check, I expect it will work with the regular UYK menu option as well. The problem is how to create that bin file in the first place without knowing Amazon's private key.

I did above process for "Update_jailbreak_hotfix_1.16.N_install.bin",
after reboot, the bin file is still there, but kindle rename the file to:
"update-3581520036-05f8861b-7390-4b4a-b721-9fb708c5e68f.bin"
is this random hex code or "key"?

[ilovejedd]

Interesting.

The 3581520036 is the Target OTA reported. The last is just a random hash.

[howtojb]

there is no way for KOA software JB,
and still can not find any information of KOA Serial Port...
no none know where is Serial Port of KOA
https://www.mobileread.com/forums/sh...d.php?t=275213