Slow but certain death of my Lime?

[cptG]

Hello!

A few days ago, the SD-card of my Lime started working, but in a very strange way:
- u-boot can access it just fine, loads boot config and kernel from the SD card
- kernel loads and is stuck at "waiting for root device /dev/mmcblk0p1"
This happened from one reboot to another, the config did not change in any way.
The same SD card boots fine on my Lime2. I tried using another SD-card with the same image - same result. I tried an older backup of my image - same result. As a workaround, I changed boot.scr on the SD card to change the kernel parameter root=... to use a USB thumb drive as its root, with the thumb drive containing the same image as the SD card does.

OK, so I can boot now but just now my touch panel went crazy. It reports event after event without any actual touch happening on it. I made sure that there is no mechanical strain on the panel (event took it out of its casing). It even keeps reporting events after I unplug the four-pin touch-connector on the LCD controller board. It only stops if I boot the board with the LCD completely detached.

Can these two problems be related? Are both devices on the same bus and it is dying on me bit by bit?

If not: what could be the cause of the issues? I suspected that I might've inadvertedly changed the sensitivity setting of the touch panel but this seems to be compiled-in into the kernel module. Or changed in the .fex, which has not been changed, at least not by me or on purpose

Versions:
- u-boot 2015.01
- kernel 3.4.103 (Arch Linux ARM)
- Lime A20, PCB says rev.E

Any help?

Thanks

Thomas

[JohnS]

What power supply?  Suspect it.

John

[cptG]

It was powered via USB (which has never been a problem)
I just re-tried with 5V from an ATX power supply, no change - no mmcblk0, batshit-crazy touch panel.

edit Just tried the same LCD on my Lime2 and it behaves the same way there, so it seems to be an issue with the panel. The ribbon cable is not the issue, I have a few of them flying around and I also tried with a brand new one.
So what remains is the question: what could be the issue with the SD card of my Lime?

[cptG]

Well, found out something strange interesting about the touch panel:

Just to be sure, I changed the sensitivity settings in the .fex file (which have been working fine for months, so much so that I completely forgot about them), which seemed to fix the issue. Out of curiosity (read: make sure I'm not crazy), I changed them back to the exact values they were before and the issue remains gone.

How can it be that the change-and-change-back solved the issue? And: how come it behaved the same way on both Lime & Lime2?

[JohnS]

Worth trying a different SD card.

Some are fakes.

John

[cptG]

JohnS, thanks for the reply!
Already did that, no difference. In fact, when booting from USB, I can switch SD-cards like crazy and I see no output in dmesg whatsoever. And: Lime2 boots from the same SD card just fine.

[JohnS]

Is it a distro where you need a different image for Lime than for Lime2?

John