I'm glad to see more people upgrading via SD card. The link
posted previously is correct in some aspects. I used live linux
CD and both usb card reader for the card and usb stick for
tarred image. The very first step has to be:
mkfs.ext3 -L Kobo /dev/sdX
Where sdX is the correct name for the device in /dev directory.
If I recall well, my usb reader was /dev/sdb and stick sdd. Your
names might be different. Doing this, the card reader has to
be unmounted. If you have auto mounting, umount it!
Next, if compressed once, simple decompression should be
enough. I urge you not to copy directory tree to your hard
disk, since there are some soft links, that should act strangely
when copied again. So, I think the best would be to mount
both usb card reader to some point like /mnt/sdcard and usb
stick to /mnt/usb. (I did it that way. If you have linux installed,
no need for usb stick, just point to the file itself.) Then do it
all in one step. Here is something that resembles what I did
for bz2 file:
tar -C /dev/sdX -pzxvf /path/to/file
SdX has to be device in /dev, that represents your usb card
reader with SD card in it (mounted, of course). I set full path
to the file, and it was, in my case, /mnt/usb/image.tbz.
My advice would be to do first try of the file simply untarring the
copy of it (since you might loose the original file) on your box
and see if this command works:
tar -zxvf file.tgz
If you get directory tree, great! You are ready to follow my
way or find your own, which is not that dangerous, since you
could try again. Once again, don't copy untarred tree to the
card. It might work, but there is a chance it might not.
I will feel free not to download and do the work myself, since I
know a lot of posters will do that themself.
Finally, I did not connect reader to the computer! I inserted the
card to the slot, pushed middle button and powered it up.
Nothing more, nothing less. I upgraded. I let it power down,
get the card out and checked if it worked. When assured, I
connected to my box and copied book directory to the mounted
device. The file sistem is vfat, msdosfs or however you name it.
After unmounting and disconnecting, it took almost an hour
to process files. As I could see, works fine now.