I recently had a hard crash on my G2 with stock firmware. The SD card was corrupted and would only mount as read-only.

The solution to fixing the a Read Only SD Card was:

1. Remove microSD card from G2
2. Put it in an external flash drive reader
3. Run a check disk with sector recovery

This got my drive working again for the G2 but things were still a bit weird. My Gallery application would not load the contents of the SD Card anymore, it looked as if there were blank spots for the folders that I used to have, but no thumb nails.

Fix for getting the Gallery Application to work properly (you need to follow the steps above):

1. Remove SD Card from G2
2. Backup Entire Contents of SD Card to a location on your computer
3. Put SD Card back into the G2
4. Go To Settings
5. SD Card
6. UnMount the SD Card
7. Format the SD Card (it is important that you format the SD Card with your G2 as it restores core system files to the card.
8. Power Cycle your G2
9. Connect your G2 to your computer and enter into USB drive mode
10. Copy back your media and music that you recognize. Do not copy back folders that you do not recognize unless you find that you need them.
11. Be sure to delete any folders that are named “.Thumbnails” Gallery will regenerate them for you
12. Power Cycle your G2 again
13. Go into Gallery and just wait. Depending on how many images and their size on the SD Card it could take a while to generate the thumbnails again.
14. All Done.

These are the steps I took to recover, others may have a better way of doing it, if so, please let me know and I will update the post.