MobileRead Forums - View Single Post - Original "Simple" debricking methods for K5-Touch, K4-Mini, & K3-Keyboard

ixtab · 07-22-2012, 11:13 PM

EDIT: Please see second edit below.

I guess something went terribly wrong here.

We finally got our hands on some 5.1.1 images. I first installed only the main partition (over the previous 5.1.0), and it worked almost smoothly. ("almost" meaning that everything except the Wifi would work). The Wifi wouldn't work because of some missing kernel symbols. Makes sense if you're not running the matching kernel.

So I went through the entire process with mfgtool and fastboot to flash the main kernel. I didn't change anything else. And now here's the situation:

Resetting to "HID mode" works.
Booting to fastboot mode works.
Booting to diags works.
Booting to main doesn't work. There's simply absolutely nothing happening. No flashing of the screen or LED... nothing. Hard resets have absolutely no effect either. The only thing that I can get back into is the HID mode.

So I thought: ok, whatever. Let's try to flash the previously working (main) kernel back onto it. It still doesn't work.

Since I can boot to diags, I can verify (using getkernels.sh) that the kernel on the device is actually the one that was flashed (md5sums match).

So... the big question is: WTF is going on here?!
Does anyone have a clue, or a hint on what could be done to troubleshoot this? As said, fastboot and diags work completely normally. Just trying to boot to main (whether using mfgtool, or by rebooting from diags) does absolutely nothing at all. For the record: I also tried to erase p3, though I didn't expect it to change anything (and it doesn't). The filesystem on p1 looks ok (and as said, it worked before).

Note: I only have USB access to the device (no serial cable or so).

Any help is really appreciated.

EDIT:
I may have found the reason for this. In fact, re-installing 5.1.0 (kernel AND partition) did NOT work. But installing 5.0.0 got the device back alive. The funny thing is the following... I flashed this 5.0.0 kernel of 5090176 bytes:

Code:

md5sum kt_5.0.0-kernel.img
ade683d89aa95b452e73778dd30058cd *kt_5.0.0-kernel.img

However, for this kernel, the getkernels.sh returned a kernel of 5090304 bytes:

Code:

md5sum main_kernel.img
f51c5478ffe8e8729c55a1988efe5dd5  main_kernel.img

I have verified that it is indeed the same file, but with a few trailing junk bytes.
My suspicion is now that the kernel is somehow checked for integrity (CRC32 or whatever, need to look this up) and is simply thrown away if something is wrong. But I need to look further into it. I'll go kamikaze and try again now with 5.1.0 and 5.1.1

07-22-2012, 11:13 PM	#460
ixtab (offline) Posts: 2,907 Karma: 6736092 Join Date: Dec 2011 Device: K3, K4, K5, KPW, KPW2	Unable to boot to main EDIT: Please see second edit below. I guess something went terribly wrong here. We finally got our hands on some 5.1.1 images. I first installed only the main partition (over the previous 5.1.0), and it worked almost smoothly. ("almost" meaning that everything except the Wifi would work). The Wifi wouldn't work because of some missing kernel symbols. Makes sense if you're not running the matching kernel. So I went through the entire process with mfgtool and fastboot to flash the main kernel. I didn't change anything else. And now here's the situation: Resetting to "HID mode" works. Booting to fastboot mode works. Booting to diags works. Booting to main doesn't work. There's simply absolutely nothing happening. No flashing of the screen or LED... nothing. Hard resets have absolutely no effect either. The only thing that I can get back into is the HID mode. So I thought: ok, whatever. Let's try to flash the previously working (main) kernel back onto it. It still doesn't work. Since I can boot to diags, I can verify (using getkernels.sh) that the kernel on the device is actually the one that was flashed (md5sums match). So... the big question is: WTF is going on here?! Does anyone have a clue, or a hint on what could be done to troubleshoot this? As said, fastboot and diags work completely normally. Just trying to boot to main (whether using mfgtool, or by rebooting from diags) does absolutely nothing at all. For the record: I also tried to erase p3, though I didn't expect it to change anything (and it doesn't). The filesystem on p1 looks ok (and as said, it worked before). Note: I only have USB access to the device (no serial cable or so). Any help is really appreciated. EDIT: I may have found the reason for this. In fact, re-installing 5.1.0 (kernel AND partition) did NOT work. But installing 5.0.0 got the device back alive. The funny thing is the following... I flashed this 5.0.0 kernel of 5090176 bytes: Code: md5sum kt_5.0.0-kernel.img ade683d89aa95b452e73778dd30058cd kt_5.0.0-kernel.img However, for this kernel, the getkernels.sh returned a kernel of 5090304 bytes: Code: md5sum main_kernel.img f51c5478ffe8e8729c55a1988efe5dd5 main_kernel.img I have verified that it is indeed the same file, but with a few trailing junk bytes. My suspicion is now that the kernel is somehow checked for integrity (CRC32 or whatever, need to look this up) and is simply thrown away if something is wrong. But I need to look further into it. I'll go kamikaze and try again now with 5.1.0 and 5.1.1 Last edited by ixtab; 07-23-2012 at 12:55 AM.*