Kernel PANIC after update

[Boomer]

I updated to the new Debian Wheezy distribution and thought everything was fine. Set the overclocking at 950. Now, however, every time I boot, I get a "panic" saying:

unable to mount root fs on unknown-block(172,2).

I have absolutely no clue how to resolve this. Any help would be greatly appreciated.

Thanks,

Jack

[elatllat]

try reverting the over clock setting

[Boomer]

I'm a total noob. Can you tell me how?

[obcd]

It's holding a key during boot. After that, you can run the raspi-config program and disable the overclocking. I just forgot which key it was. The news section points to the relevant forum article that describes it . I think it was the shhift key. (But what I think is not important.)
So, holding the key will disable overclocking for that boot session.

[Boomer]

Thanks. I thought so too and had tried it before my initial post. Will try it again. If it doesn't work I guess I'll reformat my SD card and try again....

J.

[stevotdo]

1)Reinstall image on sd card
2)Don't overclock for now
3)Wait until the issue with the new firmware is sorted

Something with the new firmware and the way it now handles overclock is corrupting sd cards.

I do not know if it is specific to certain brands of sd cards at the moment or board versions.

Out of curiousity, what sd card are you currently using?

[Boomer]

Transcend 32G, Class 10. Listed as compatible.

Realized, I can't use the shift key to boot into "safe" mode because the PANIC occurs before the keyboard is recognized. No choice but to reformat the SD card with the new distro and try again.

Nothing like being clueless and on the bleeding edge....

However, one small sweet revenge -- I've given Pis to two of my kids, both of whom claim to be much smarter than I. Now I get to watch them squirm too!!

J.

[RaTTuS]

you could edit the config.txt file in a windows machine using notepad++

[Boomer]

Maybe, if I knew how. How would I get the file from my machine to the Pi if I can't boot it? Or are you saying I should edit the config.txt file by putting the SD card into my PC and then put the SD card back in the Pi once I'm done? Assume the only change would be to delete the overclocking stuff....

This stuff is hard for us mere mortals....

[Paul Webster]

Yes - that is a way to do it (edit on Windows machine)

[obcd]

The sd card contains 2 partitions. The boot partition is 50 - 70MB in size and is a fat(32) partition that you can also acces from a windows computer.
The other is an ext4 partition that can only be mounted on a linux machine and contains the linux root filing system.
The boot partition contains besides the kernel and the startup binary blob, the config.txt and cmdline.txt files that describe how the kernel should boot.
(And it seems the dynamic overclocking setting is hiding in one of those files as well.)
I hope this helps a bit in understanding things?