To install twrp on lollipop i need to downgrade laf and aboot partions following this
http://xdaforums.com/lg-g2/development/guide-bumpedtwrp-recovery-stock-v30d-t3070365
Ok but, i am a little curious, why i need to change these partitions to v20b?
And what does laf and aboot contain?
Second question, after i did it,
can i flash/update the twrp normally? Flashing the one provided on official twrp website?
Third question,
every rom work on lollipop bootloader?
aboot is the bootloader partition, laf is the download mode.
The bootloader is the first partition that starts the phone.
It has the particular role of checking that the result of the boot can be carried out.
Following, the boot continue with the kernel (or recovery). The bootloader checks before the kernel can be launched, watching it bears a signature that proves its integrity.
if the kernel is not the original, it does not contain the desired signature and the bootloader does not start it (security boot error).
So we can't have custom recovery or custom kernel, without bypassing this method of verification, included in the bootloader.
The first solution was loki, but it just worked with JB bootloader. LG had patched loki on the KK booloader. So, when KK arived, we had to downgrade aboot (bootloader) for being able to boot a KK lokified kernel (and lokified recovery).
After, another workaround was found by the team codefire: bump! Bump can add the original signature to the kernel (and recovery). it worked with the kk bootloader and JB bootloader but no more with LP bootloader.
So for continuing to exploit Bump! with LP, we have to downgrade aboot (bootloader), like we did for loki in KK.
So for LP, we have to downgrade aboot (bootloader) to a KK version, bump recovery, and bump LP kernel for injecting inside the KK signature that KK bootloader is waiting.
I don't think original twrp is bumped, so don't flash it with a kk bootloader.
Note: loki is generally made on the fly (the process is made during the flash). Bump can be done before the flash or during the flash (live bump).
Last note, bootloader check if the download mode is correct too (laf), if its version is good, and doesn't start it if it dosen't match. So if we downgrade bootloader, we have to downgrade laf too.
boot is the kernel partition.
Today, in the light of what I just explained, no other rom than original can start with a LP bootloader.
references:
loki:
https://github.com/djrbliss/loki
http://blog.azimuthsecurity.com/2013/05/exploiting-samsung-galaxy-s4-secure-boot.html
bump:
http://xdaforums.com/lg-g3/orig-development/bump-sign-unlock-boot-images-lg-phones-t2935275
http://xdaforums.com/lg-g3/orig-development/fix-sharpening-mod-script-1-0-beta-t2957648
http://xdaforums.com/lg-g2/help/bum...llipop-ota-t3068873/post59806620#post59806620
partition extractor from kdz:
http://xdaforums.com/showthread.php?t=2483250
http://xdaforums.com/showthread.php?t=2600575
and custom recovery story on the G2:
http://xdaforums.com/showthread.php?t=2667227
http://xdaforums.com/showpost.php?p=51512054&postcount=5003
http://xdaforums.com/showthread.php?t=2715496
http://xdaforums.com/showpost.php?p=56082714
https://github.com/JackpotClavin/an...mmit/7b6187a0e5fb8ca59888cacf5f5b863baa8d1064
