[AT&T Samsung Galaxy S II SGH-I777] Lanchon:
Brickbug Aftermath: Speeding up the Galaxy S2 i9100, S2 AT&T i777, S2 Epic 4G Touch d710 and Note n7000

UPDATE: VICTORY !!!

2016-03-02: after two years of tests and discussions, folklore, FUD and evidence, Lysergic Acid finally took the plunge and merged! TRIM is now part of the official CM 12.1 and CM 13.0 kernels, and this project can at last be retired, yoohoo!!! CM 13 users now enjoy TRIM out of the box, but users of CM 12.1 builds older than Match 2016 as well as CM 11.0 users continue to require a separate TRIM kernel.

this thread is dedicated to Entropy and the brave users who risked their devices to run the very first TRIM tests.​

UPDATE: CM 13.0 kernels are now available!!! (for CM 13.0-supported platforms only: i9100 and i777.)

UPDATE: several enhancements in new kernel batch:

CM 12.1 kernels are now available!!! (for CM 12.1-supported platforms only: i9100 and i777.)

kernels can now be flashed with the official, restricted cyanogen recovery that is bundled with CM 12.1.

rom-independent kernels: kernels are no longer dependent one-to-one on specific official CM builds (they might work with other roms too), and their names no longer reference a specific CM build.

although there are no official CM 11 builds for the i777, thanks to rom independence CM 11-based kernels for that device are now available.

CM 11 i9100-to-i777 cross-flash kernels for the i777 may now work with other i9100 roms besides official CM.

UPDATE: Crossflash Kernels for the i777

CyanogenMod stopped supporting the i777 in the CM 10.2 days and never produced CM 11 roms for this device. in the past, availability of my TRIM kernels for this device was limited in the same way.

now I have released crossflash kernels for the i777 that allow you to flash official i9100 releases of CM 11 on your i777 and enjoy CM 11 plus TRIM and FPBug fix. in other words, a fast and stable CM 11!

UPDATE: CM 13 Crossflash Kernels for the i777 are now available here.

Instructions

download a version of CM 11 for the i9100 to your phone.

(until M13 is released, i recommend the latest nightlies over M12. switch to M13 afterwards.)

download a more-or-less matching version of my i777 crossflash kernel to your phone.

(kernel and rom versions do not need to match exactly; most combinations will work.)

boot into recovery

flash my kernel.

reboot recovery.

flash the official i9100 CM 11 zip file.

(do not modify the file in any way! my crossflash kernel will adapt it to the i777.)

flash my kernel again.

finally, i recommend that you trim partitions to gain increased speed.

(follow the relevant steps of the "instructions" section of this post.)

NOTE: the next time you upgrade CM you can skip steps 4 and 5.
​

UPDATE: this project now supports all roms and kernels!

if you are not running CyanogenMod M snapshots, please see this post.

this project restores TRIM capability to CyanogenMod kernels for the Galaxy S2 family of 4210-based devices: i9100, i777, d710 and n7000. TRIM is needed to avoid "aging" of the state of the eMMC, the internal flash storage, that eventually slows the device to a crawl. TRIM functionality is built into android 4.3 and later. however, due to historical and safety concerns, TRIM capability was removed from the CM kernels for these devices (and from most if not all other AOSP-based kernels).

STOP!!! DRAGONS AHEAD!!!

in theory there could be risk of hard-bricking your device forever.

1) READ THIS POST IN FULL.

2) answer this poll (view results).

3) discuss your i777 experience below in this thread.

Downloads

for the supported devices, you will find IsoRec-compatible CyanogenMod-based kernels here. (old kernels without IsoRec support can be found here. yet older retired kernels without FPBug fix are still available here.) note that for some supported devices, no releases or M snapshots are currently being produced. for those devices i can produce kernels based on known 'stable' nightlies if users ask.

XDA:DevDB Information

BrickbugAftermath-i777, Kernel for the AT&T Samsung Galaxy S II SGH-I777

Contributors

Lanchon

Source Code: https://github.com/Lanchon/BrickbugAftermath-SGS2

Kernel Special Features: CyanogenMod kernel with TRIM support

Version Information

Status: Beta

Created 2014-09-13

Last Updated 2016-03-15