[Q] Black screen after bootanimation - G Tablet Q&A, Help & Troubleshooting

Hiya people..
So I was on the first Beta by Team DRH ICS but decided to go back to Beastys.
I went to CWM, wiped everything, installed the beastys.zip and rebooted the G-Tab.
But now when I turn the G-Tab on the screen is just black after the "Notion Ink" bootanimation..
I've tried NVFlashing 4349 Rev4 with the CWM Touch 5504 B14.
Tried with Calkulin+ClemsysFroyo and Beastys+ClemsysFroyo, also tried with and without the SOD Fix for Froyo ROMs.
If I just let the G-Tab boot after the NVFlash it works, it boots up to the TnT ROM.
I've also tried unplugging the battery for 15 sec or so, and pressing the internal reset button.. Still no luck =/
Anyone at all got any clue on how to fix this? =/

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ZoZo- said:
Anyone at all got any clue on how to fix this? =/
Click to expand...
Click to collapse
Do these two things:
1. Boot into CWM, run this ADB command and post the output.
Code:
C:\SOME\PATH> [B]adb shell fdisk -l /dev/block/mmcblk3[/B]
2. After installing the ROM of choice in CWM, and before rebooting into the ROM for the very first time:
- power off the gTab
- connect the USB cable to PC.
- run this ADB command on the PC (and keep it running until you encounter the black screen):
Code:
C:\SOME\PATH> [B]adb logcat -v time > logcat.txt[/B]
- now power on the gTab.
This sequence will ensure that all the logs are collected, and right from the start. Kill the log collection after some time and post that output here too.

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Ehum... Could the adb shell fdisk -l command have done anything?
Because after another NVFlash 4349 > NVFlash CWM Touch > Flash Beastys... It magically works!
I couldn't initiate any logcat, only get "waiting for device"

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ZoZo- said:
Ehum... Could the adb shell fdisk -l command have done anything?
Click to expand...
Click to collapse
If you ran the fdisk while in CWM, then no--the fdisk was just a diagnostic command.
I couldn't initiate any logcat, only get "waiting for device"
Click to expand...
Click to collapse
That is how it should be. ADB will wait until the device is booted up and the ADB server on the device runs.

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Different tablet, same problem
This is same topic, but a different tablet.
A friend on mine purchased Xtex MyTablet 7" (ICS); after about a week, the tablet boots into a "blank" screen, after running two bootanimations.
I ran "adb logcat" and can see the system processes running, but screen stays blank, making the tablet unusable.
I ran "adb logcat -v time > logcat.txt" and here is the file:
https://dl.dropbox.com/u/18476770/Android/logcat.txt
This tablet being fairly new, I could not find any support forums for it; I opened a ticket with the supplier, but they are very slow responding.
I turn to XDA, knowing the knowledgeable and helpful people here will shine some light my way.
Thank you in advance
./B

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kozmo2k4 said:
This is same topic, but a different tablet.
A friend on mine purchased Xtex MyTablet 7" (ICS); after about a week, the tablet boots into a "blank" screen, after running two bootanimations.
Click to expand...
Click to collapse
Since I don't have that tablet, it's difficult to do comparisons to determine deviant behavior. So, what follows are just guesses:
1. There is this error message in that log which might be relevant (or it might not--I've no idea):
Code:
06-12 21:12:30.659 E/SurfaceFlinger( 85): couldn't find an EGLConfig matching the screen format
06-12 21:12:30.729 E/DisplayDispatcher( 85): Open Display Device Failed!
06-12 21:12:56.849 E/DisplayManagerService( 149): Open Display Device Failed!
2. I noticed that some 3rd party live wallpapers were being loaded. Did the problem start after the live wallpapers were installed? Maybe that's causing problems.
Given that you are able to see 2 (?!!!) boot animations before the display goes blank, I would have to guess that its no. 2 (heh!) that's causing problems. Uninstall all the live screensaver packages using ADB. Use this as a guide.
As a last resort, you could try going into CWM (if it's installed) and do a "wipe data/factory reset", then re-install the ROM. You will lose all data with this.

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Thank you for the fast reply, rajeevvp.
I'm sorry I said it wrong earlier, there is only one boot animation, the "old school" letters: ANDROID, with a light beam running across them. There are two "boot logos" that flash on the screen prior to that. My PC, right now logged in on Win7x64, recognizes the tablet connected (USB device connected jingle) at the Android bootani.
I'm going to try to adb uninstall some of the apps and we'll see what happens.
Thanks for the insight.
./B
[EDIT]: Unfortunately, no CWM installed. I can't even figure out any kind of recovery on this. Only physical buttons are: Power, Menu and Escape. I tried all combinations, but it just boots up.
---------- Post added at 05:23 PM ---------- Previous post was at 04:50 PM ----------
Follow up:
ADB has root access, I can browse all directories (i.e. /data/data)
adb uninstall, all I get is "Failure"
In adb shell, after remount rw, command: rm -f /data/app/.apk
says "No such file or directory"
I know I typed the package name (com.cellfish.livewallpaper.marvel_avengers-1.apk) correctly. Hmmm
./B

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kozmo2k4 said:
Follow up:
ADB has root access, I can browse all directories (i.e. /data/data)
adb uninstall, all I get is "Failure"
Click to expand...
Click to collapse
What is the exact command you used? As the document says, if you are using ADB, you should do:
Code:
C:\SOME\PATH> [B]adb uninstall [I]packagename[/I][/B]
Unfortunately, no CWM installed. I can't even figure out any kind of recovery on this.
Click to expand...
Click to collapse
If you can figure out how to get into stock recovery (it would be very unusual to not have one--its needed for ROM upgrades for instance), then you could try this:
Clear Cache and Data from Stock Recovery

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Thank you for the reply.
Here is what I've tried:
Code:
adb uninstall com.cellfish.livewallpaper.marvel_avengers-1.apk
then the app full name I found in Play Store
Code:
adb uninstall The Avengers Live Wallpaper
Al I get is "Failure"
Next I tried
Code:
adb shell
[email protected] # mount -o rw,remount /data
[email protected] # rm -f /data/app/com.cellfish.livewallpaper.marvel_avengers-1.apk
The I get:
rm failed for -f, No such file or directory
I was not able to figure out how to get to recovery of any sorts; like I mentioned, only 3 physical buttons, Power, Menu and Esc. Tablet has microSD slot, Mini HDMI, 3.5mm headphone, Mini-B USB and full USB ports. That's all. I'm getting close to opening the case to see if there is a reset button, but waiting for my colleague's pernission (she'll most likely just send it back).
Update:
I was able to remove the live wallpaper in adb (just omitted the -f after rm), but no cookie....black screen after boot.
Is there a way to wipe-factory reset with adb? Just delete the contents of /data/app directory? .... Only one way to find out...
---------- Post added at 06:22 PM ---------- Previous post was at 05:59 PM ----------
Update II:
Code:
adb shell wipe data
did the trick, tablet booted up just fine (except for the Chinese language...lol).
Thank you again for all your help!
Linux ROCKS
./B

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Follow up post
Just a follow up:
A couple of days later, my colleague had brought the tablet back with black screen again.
After a little "interrogation", I found out that she actually hit the brightness button on the Power Widget a couple of times and that had dimmed the background light to ZERO.
Having more information than before, I've came across two possible solutions:
1. Use LED flashlight and shine it on the screen at a certain angle and try to make out the icons on the (LCD) screen and re-adjust the brightness...
2. Use Droid Explorer with the "Screen Cast" java applet to mirror the screen on a PC and try to adjust the brightness that way.
3. Try to reset the brightness sqlite database (way out of my league; I'm a "hardware guy", not a programmer...)
Well, number 2 was the winner!
So, for future reference, if anyone get "black screen only" and have ADB set up on your PC, use the Droid Explorer (http://de.codeplex.com/) with Screen Cast plugin to access you Android device.
I hope this will help someone....

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kozmo2k4 said:
Code:
adb uninstall com.cellfish.livewallpaper.marvel_avengers-1.apk
Click to expand...
Click to collapse
You have to use the package name and not the apk name to adb uninstall. Look inside the /data/system/packages.list file to determine this.
Update II:
Code:
adb shell wipe data
did the trick, tablet booted up just fine (except for the Chinese language...lol).
Click to expand...
Click to collapse
A bit drastic, but, that works . But, I wouldn't have recommended wiping the /data partition like that while inside the ROM. This is why a recovery mode exists.
I wouldn't be surprised if after a wipe like that and a subsequent filesystem check, the /data/lost+found directory contained more than a few files/dirs.
---------- Post added at 11:16 PM ---------- Previous post was at 11:13 PM ----------
kozmo2k4 said:
Just a follow up:
A couple of days later, my colleague had brought the tablet back with black screen again.
After a little "interrogation", I found out that she actually hit the brightness button on the Power Widget a couple of times and that had dimmed the background light to ZERO.
Having more information than before, I've came across two possible solutions:
1. Use LED flashlight and shine it on the screen at a certain angle and try to make out the icons on the (LCD) screen and re-adjust the brightness...
2. Use Droid Explorer with the "Screen Cast" java applet to mirror the screen on a PC and try to adjust the brightness that way.
3. Try to reset the brightness sqlite database (way out of my league; I'm a "hardware guy", not a programmer...)
Well, number 2 was the winner!
So, for future reference, if anyone get "black screen only" and have ADB set up on your PC, use the Droid Explorer (http://de.codeplex.com/) with Screen Cast plugin to access you Android device.
I hope this will help someone....
Click to expand...
Click to collapse
+1 kozmo2k4. We need more smart users like you on the board.

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Thank you for the kind words, rejeevvp. I love to "tinker" with things and do not give up that easily.
I know the "adb shell wipe data" was an overkill, like chasing a fly with a .50cal, but at that point in time it was the most feasible.
I've tried all possible button combinations to get into recovery, but everything led to regular boot.
After the successful booting into the ROM, I did notice an option under settings>development to boot Recovery. Which I did, and was presented with a basic "blue" Android System Recovery .
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
I did another Wipe Data and wipe Cache and rebooted.
Everything seemed to be working fine afterwards, and my colleague texted me that the tablet is running faster and smoother than when she first got it, so everything is all good.
[Edit] Funny thing I just noticed, in the picture it says to use (Q7, volume up/volume down, Home, Enter), however, there were no "hard" buttons labeled that, only: Power, Menu and Escape!
Here is the front:
Sent from my NookColor CM9 using Tapatalk 2

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kozmo2k4 said:
After the successful booting into the ROM, I did notice an option under settings>development to boot Recovery. Which I did, and was presented with a basic "blue" Android System Recovery .I did another Wipe Data and wipe Cache and rebooted.
Click to expand...
Click to collapse
+1 again. That is the right thing to do.
[Edit] Funny thing I just noticed, in the picture it says to use (Q7, volume up/volume down, Home, Enter), however, there were no "hard" buttons labeled that, only: Power, Menu and Escape!
Click to expand...
Click to collapse
Tried the soft buttons? ...but, yeah, that's Android for you--basically not a lot of QA going on anywhere. Even the top guns like Asus seem to be asleep at the switch.
BTW, I think I've found where the screen brightness level is stored--at least for Gingerbread. Care to run a few test commands with that tablet?

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Reset Brightness
rajeevvp said:
+1 again. That is the right thing to do.
Tried the soft buttons? ...but, yeah, that's Android for you--basically not a lot of QA going on anywhere. Even the top guns like Asus seem to be asleep at the switch.
BTW, I think I've found where the screen brightness level is stored--at least for Gingerbread. Care to run a few test commands with that tablet?
Click to expand...
Click to collapse
Soft buttons work while in ICS; when tablet was off, only "hard buttons" were available.
I would be more than happy to run few tests, but I returned that table on Sunday (have the feeling that wasn't the last time I saw it, though).
During my "research", I came across these possible locations of brightness setting on ICS:
/sys/class/backlight/rk28_bl/brightness
or
/sys/class/leds/lcd_backlight/als
(however, I don't see "rk28_bl" or "lcd_backlight" on my gTablet ICS 4.0.4, or my SPH-D710 2.3.6 under /sys/class; I have "/sys/class/pwm-backlight/" tree on both devices:
There was also a script to reset brightness to 100% in sqlite database
Code:
#sqlite3 /data/data/com.android.providers.settings/databases/settings.db
sqlite> update system set value=255 where name='screen_brightness';
sqlite> .exit
#reboot
But I did not get to try any of that, since I got lucky with Android Commander and ScreenCast.

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kozmo2k4 said:
During my "research", I came across these possible locations of brightness setting on ICS:
/sys/class/backlight/rk28_bl/brightness
or
/sys/class/leds/lcd_backlight/als
(however, I don't see "rk28_bl" or "lcd_backlight" on my gTablet ICS 4.0.4, or my SPH-D710 2.3.6 under /sys/class;
Click to expand...
Click to collapse
Everything under /sys/ depends on the kernel. Some files and directories are standard, some, like the above, are not.
I have "/sys/class/pwm-backlight/" tree on both devices:
Click to expand...
Click to collapse
Interesting...don't have that on the pershoot kernel. Try fiddling with the values in "brightness" as root.
There was also a script to reset brightness to 100% in sqlite database
Code:
#sqlite3 /data/data.com.android.providers.settings/databases/settings.db
sqlite> update system set value=255 where name='screen_brightness';
sqlite> .exit
#reboot
Click to expand...
Click to collapse
+1 again. The path is different (/data/data/...) but that's what I meant. There is also the 'screen_brightness_mode' setting. 1 => Auto brightness, 0 => manual brightness, I think. You may need to change both.

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rajeevvp said:
Everything under /sys/ depends on the kernel. Some files and directories are standard, some, like the above, are not.
Interesting...don't have that on the pershoot kernel. Try fiddling with the values in "brightness" as root.
+1 again. The path is different (/data/data/...) but that's what I meant. There is also the 'screen_brightness_mode' setting. 1 => Auto brightness, 0 => manual brightness, I think. You may need to change both.
Click to expand...
Click to collapse
That was a TYPO on my part (fixed on original post for future reference).
My gTablet is on ICS (actually I just flashed AOKP, running pretty good so far) with TeamDRH kernel. My phone is on stock EL29-repack (Calkulin's v3.0) kernel.
Hope all this info will come in handy for someone in the future!

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I am glad you were able to solve this issue for your friend because I did exactly the same thing as she did and now I have black screen.
I could not follow all the discussion so, is it possible to dumb it down so I can repeat what you did to fix that XTEX tablet?
Thank you

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fazluke said:
I am glad you were able to solve this issue for your friend because I did exactly the same thing as she did and now I have black screen.
I could not follow all the discussion so, is it possible to dumb it down so I can repeat what you did to fix that XTEX tablet?
Thank you
Click to expand...
Click to collapse
Do you have ADB.set up on your PC?
If so, go ahead download and install Droid Explorer (there is a link few posts back).
Once installed, run it, ensuring you "powered on" tablet is recognised. Along the top row of icons, there is one called Screen Cast (hovering over the icons will show the name). Select it, let the Java applet install, then click Screen Cast and that should open a new window, mirroring the tablets screen. Then you can navigate on the tablet to settings.... and get it set.
I think there may be a video on YouTube showing this.
Hope this will help.
[Edit] Here is a link to Youtube:
http://www.youtube.com/watch?v=eEeHaszOMi0&feature=youtube_gdata_player
Sent from NOOK Color CM7.2 using Tapatalk 2

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Thanks for the quick response, will download and follow your directions, then report back tonight.

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fazluke said:
Thanks for the quick response, will download and follow your directions, then report back tonight.
Click to expand...
Click to collapse
Worked exactly as described with minor issue. Screen cast does not work on locked device. I see the locked screen but can't unlock it and the Youtube link confirmed that too.
I tried to turn it off and on, to see if I can get hold of it before it goes into locked mode and after few tries I got it to work.
Another issue was that my mouse will not control it. SO looking at the computer screen and moving my finger on the tablet surface, I managed to get to setting/display and adjust brightness.
Thank you again for your help.