Problem with 512MB Pi

[udrnovsek]

Just a hint. I had similar problems and i found this solution.
After burning an image. I mount SD cart on my laptop and edit config.txt
I comment all lines about any frequency.
So my /boot/config.txt looks like this:

disable_overscan=1
gpu_mem_256=100
gpu_mem_512=100

From that time, no problems.
(just after plugging off the working raspi, SD card gets corrupted)