TWRP recovery shows black screen in klimtwifi

[noobody01]

TWRP recovery images built for the Samsung Galaxy Tab 8.4 SM-T700 (klimtwifi) boot to a black screen. The tablet is recognized when connected to a PC, suggesting that TWRP is running, but either the display is not functional or its brightness is set to a very low level. The default Cyanogenmod recovery images produced using a nearly identical build environment do not show this problem (changes in setup noted below).

I compiled TWRP under a Cyanogenmod 12.1 base using the shell commands shown below. The Cyanogenmod base was downloaded using the build-manifest.xml I pulled from my Galaxy Tab SM-T700. (Some intermediate commands maybe missing as I'm typing this partly from memory. Git sources are current as of 2015-07-06.)

$ croot
$ cd bootable
$ rm recovery -fR
$ git clone https://github.com/omnirom/android_bootable_recovery
$ mv android_bootable_recovery recovery
$ croot

I then edit device/samsung/klimtwifi/BoardConfig.mk, adding only the line:

DEVICE_RESOLUTION := 1080x1920

To ensure shell environment is clean, I log out and start a new shell session.

$ cd ~/CM12/system
$ source build/envsetup.sh
$ breakfast klimtwifi

(There were no errors after this step)

$ mka clean
$ time mka recoveryimage

The build finishes and successfully outputs both boot.img and recovery.img. I flash recovery.img using the following commands. This is the same set of commands I use to successfully flash and reboot into the default Cyanogenmod recovery.

$ adb root
$ adb push recovery.img /storage/sdcard1/recovery.img
$ adb shell 'busybox dd if=/storage/sdcard1/recovery.img of=/dev/block/mmcblk0p10 ; sleep 10 ; sync ; sleep 10 ; echo Hopefully done!'
$ adb reboot

The tablet reboots but after the Samsung logo all I see is a black screen. The tablet appears to be recognized as shown by the relevant entries in "lsusb" and "dmesg".

[SdtBarbarossa]

i dont know why this happens... but it is not recommended to build from cm sources ...omni would be optimal

[noobody01]

I know, only problem is there's no klimtwifi (Samsung Galaxy Tab SM-T700) support under OmniROM and I don't know how to merge the CM klimtwifi device and kernel trees with OmniROM. It seems much easier just replacing the CM bootable/recovery directory with OmniROM recovery (which defaults to TWRP).

[SdtBarbarossa]

show me your device tree please

[noobody01]

What do you mean by "device tree"? Which file or files? The source I use for building is mostly Cyanogenmod 12.1 except for bootable/recovery.

[SdtBarbarossa]

device tree is YOUR device sources ... so i guess you use this device tree:

https://github.com/CyanogenMod/android_device_samsung_klimtwifi

am i right?

[SdtBarbarossa]

remove this line in boardconfig may help: BOARD_USE_CUSTOM_RECOVERY_FONT := \"roboto_23x41.h\"

[SdtBarbarossa]

also if you are under cm sources make sure to have this commit http://review.cyanogenmod.org/#/c/89474/

as it is needed

[noobody01]

remove this line in boardconfig may help: BOARD_USE_CUSTOM_RECOVERY_FONT := \"roboto_23x41.h\"

I did another clean build following your suggestion, but when I boot to recovery using the new image, the screen still shows up as black. I'm convinced this isn't merely a font problem since even the TWRP splash curtain (which is a PNG graphic and not text) doesn't appear.

[Dees-Troy]

adb pull /tmp/recovery.log when TWRP boots to a black screen. If you get a log we will have a much better idea of what is going on. Otherwise you are just blindly stabbing. And no, it's not a font issue. I have never seen the font have an affect on whether TWRP boots in 4 years of recovery development.

[noobody01]

That was the first thing that came to my mind. However, none of the TWRP recoveries (including one prebuilt version from the TWRP site) I installed autostarts adbd. I thought this was normal for TWRP (unlike CM recovery which turns it on at startup). Therefore I can't do an "adb pull" since I have to manually start the adbd server on the tablet, and this is difficult if not impossible to do when the screen is black or totally non-functional.

Is there some change I can do to the init scripts or build to make adbd autostart?

[CaptainThrowback]

-userdebug and -eng builds should set ro.debuggable=1 by default, as least if you're using the stock init.rc. Are you using a custom init.rc with those lines missing (or not building a userdebug or eng build)?

[delve2981]

i m facing the same exact problem.my system is wrking fine but only black screen after recovery mode. plz help fast.

[tvladan]

Same issue using latest twerp on dogge dg700 lollipop mtk6582, no debugging, black screen than android boots up... Pls help/ advice? Or request what files from my system are needed to upload here in order to solve this....

[Andygumpp]

I too have the issue of black screen when booting into recovery in LG G2 VS980 Verizon. I had stock KitKat 26a with TWRP 2.7.0.0 and I flashed CyanogenMod 12.1 which worked fine. I still had the same TWRP recovery, working fine. I then used Flashify to try to flash CWM Touch recovery, and I got the boot logo for LG as usual, then some tiny white writing and black screen. Then, I tried to use Flashify to put TWRP on, and same screen. It acts like it flashes the recovery, but its so fast, I have my doubts that it is doing anything. I have also tried to use Goo and ROM Manager, but neither do anything different. If I hit the up button and hold the power I can get into download firmware mode, and if I hold the down button and power and release and rehold both at the boot LG logo, it takes me into the full factory restore screen, which is promising, but I have serious reservations about how that would work without a solid recovery in place! One thing, I notice Flashify states that my current recovery is still TWRP 2.7.0.0. I tried to even flash the zip as well as whatever TWRP was downloaded by their program. If anyone can figure this out I will name my firstborn after them! Thank you.