I've patched the OS2006 kernel and my Kingston 2 GB memory card seems to work except that I can't access it on my computer via USB. I tried to mount /dev/sda1 on my Debian Sarge system and it can't find a vfat filesystem on the device. I've tried a 1 GB card and it works via USB too.

With 2 GB memcard:
I took a raw dump (with dd) of the beginning of /dev/sda1 on my PC and indeed, there' s no FAT filesystem there. The dump consists mostly of zeroes except for "SWAPSPACE2" strings 4096 bytes apart. I guess it's a dump from somewhere in the middle of the memcard. If I take a raw dump of the beginning of /dev/mmcblk0p1 on my N770, I get the normal FAT filesystem header etc.

With 1 GB card I get an equal raw dump on both (PC and N770).

Addressing problem? Any advice?

fdisk -l /dev/sda

what is the output? does it work in 770?

It works now. Apparently a partition table refresh problem on the computer or something of that sort. I had a 1 GB MMC card which worked on N770 and mounted properly on my computer. Then I changed a 2 GB card into N770 and it worked in N770, but didn't mount on my computer. Rebooting the computer helped (except that if I put the 1 GB card back, then that doesn't mount on the computer without rebooting it.)

Did you unmount the card before changing it?

Yes. I found that "sfdisk /dev/sda" followed by ctrl-c also helps and avoids the reboot. I guess the kernel just doesn't properly refresh the partition table.