[Defy Q&A, Help & Troubleshooting] cmuelle8:
I've had the trouble described in

http://xdaforums.com/showpost.php?p=49962954&postcount=1775

What's worse, more recent builds have a kernel that bootloops for me. This thread has a solution.

Originally I was unsatisfied with CM11 nightly, because the camera crashed with a hard reset - heavy use of the gallery or taking a photo after a long time had triggered this hard reset reliably. So this problem was reproducable.

I upgraded CM11 nightly to latest 2014-03-30, just to find out recent kernels won't start at all or bootloop the green lense defy.

After that I wiped anything - flash SBF, Framaroot, 2ndinit, twrp_recovery_2.6.3.0.zip.

To confirm the device was working I flashed a couple of roms (CM9, CM10) builds from October 2013, they worked.

While testing I realized that these roms were a lot snappier than the CM11 one I was dissatisfied with, noticing that besides hard reset on camera usage I also had a lagging UI. I assume that SELinux might be one of the reasons for the camera hard resets I experienced, but have no proof for this..

Then I spent a couple of days debugging the problem and it turns out, that all of the problems arise indeed from the kernel used.

Atm, I run a butter smooth CM10.2 nightly rom dating 2014-03-31, but running on a kernel dating 2014-01-20 (ripped out of CM11-nightly!).

For this to happen, simply exchange zImage under /system/bootmenu/2nd-boot/

Extract zImage from 2014-01-20 rom beforehand, put it on sdcard.

After installing the latest rom, before rebooting, do

- Mount /system with TWRP

- Go to Tools > Filemanager

- Select the 2014-01-20 zImage in TWRP Filemanager

- Let TWRP copy it to /system/bootmenu/2nd-boot/ (overwriting the one that's in there)

- Wipe cache/dalvik

- Reboot

I have tested this setup and it runs amazingly! I tested GPS turning on an off, Camera works (except video with stock app), Wifi works - no reboots and the UI is a breeze. It simply behaves as it should. Neither zRAM or zCache is activated, battery consumption is low, as is CPU usage.

Conclusion: The latest nightly kernels suck hard for green lense defy, but I still do not know exactly why.

Fazit: Can confirm that zImage from 2014-01-20 is tried and tested.

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How solution was found: I read in the forums, that update-recovery.zip contains a kernel. Since after flash of CM10.2-2014-03-31 I had bootloop problem, I went to TWRP recovery on blue led, which still worked, and installed update-recovery.zip AFTER rom. Normally, you do not do this, since this DOWNGRADES kernel. But if latest kernel does not work, there is a chance succeeding with this method.

Ok, after flashing update-recovery.zip zImage dating 2013-11-07 was in place and phone booted with CM10.2-2014-03-31 image. I thouhgt I had found the solution, but soon noticed, that this kernel had issued with GPS (it would hang and not turn off, once activated). The immediate next step was to look for a kernel built after 2013-11-07 - I tried with 2014-01-20, since this was the latest version offered by defy.bytekiste.de here:

http://defy.bytekiste.de/cm11-nightly-defy+/

Since, on defy.bytekiste.de CM10.2 listing stopped at 2013-10-30, and with update-recovery.zip I already had a kernel from 2013-11-07, I jumped to CM11 roms, as I did not know about existence of defy.svolkov.name at that time.

defy.svolkov.name lists CM10.2 nightly builds from 2014-01-09 on. One could probably try the kernels directly from these roms. However, I think the difference in kernels between CM10.2 and CM11 is neglectible. What matters is the timestamp of the builds - different timestamp, different kernel config and that seems to decide whether it's working on defy green lense or not.

===================================

I did not further bisect the problem yet, i.e. trying each nightly kernel built after 2014-01-20 in succession to see which build first caused the bootloop problem. However I've checked some of the roms and the file structure on quarx2k.ru and defy.bytekiste.de (you can find complete structure of both on http://defy.svolkov.name/), it's borked:

versions for cm-11-20131229-NIGHTLY-mb526.zip

886b1bfdeadada2f45c695e34e126d0c http://defy.bytekiste.de/cm11-nightly-defy+/cm-11-20131229-NIGHTLY-mb526.zip

886b1bfdeadada2f45c695e34e126d0c http://defy.svolkov.name/quarx2k.ru/cm11.0-nightly-defy+/cm-11-20131229-NIGHTLY-mb526.zip

versions for cm-11-20140117-NIGHTLY-mb526.zip

a936c82ad55fa488079b2a8796838678 http://defy.bytekiste.de/cm11-nightly-defy+/cm-11-20140117-NIGHTLY-mb526.zip

a936c82ad55fa488079b2a8796838678 http://defy.svolkov.name/quarx2k.ru/cm11.0-nightly-defy+/cm-11-20140117-NIGHTLY-mb526.zip

6e05a8e9205f30a212be5aafc6e4bc01 http://defy.svolkov.name/quarx2k.ru/roms/defy-cm11.0/cm-11-20140117-NIGHTLY-mb526.zip

now, from the above, if you thought

"defy.bytekiste.de/cm11-nightly-defy+" and

"defy.svolkov.name/quarx2k.ru/cm11.0-nightly-defy+"

were mirrors wrt same-named files, think again.

versions for cm-11-20140120-NIGHTLY-mb526.zip

0602c6090ffa169dcf249b49f3c1d2be http://defy.bytekiste.de/cm11-nightly-defy+/cm-11-20140120-NIGHTLY-mb526.zip (appears to have a different ramdisk-recovery, other files in 2nd-boot dir are identical to rom below)

d9a88dde07c06474d60dc353c53babc8 http://defy.svolkov.name/quarx2k.ru/cm11.0-nightly-defy+/cm-11-20140120-NIGHTLY-mb526.zip

also note,

"defy.svolkov.name/quarx2k.ru/roms/defy-cm11.0/"

holds the most recent list of nightlies, while the listing starts with

20140109 version, and continues until

20140117 version (see versions above)

it omits 20140120 completely, and then continues from

20140123 version.

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I actually wanted to post this in dev forums CM10.2 on defy thread, but do not have more than 10 posts on xda-dev, so are not allowed to. This is why I post it here.