I just installed 51-3 last night, and my internal Transcend 16GB SDHC would not longer be recognized this morning. The only thing I have done since was to set up my voipbuster account.

Installed apps include vagalume, canola, mauku, greasemonkey, camera, and GPS City Guide.

When I connect my N800 to my notebook, Windows 'sees' two removable drives. Clicking on the external card shows the data on that card, while clicking on the internal card throws an error asking me to insert a card into the drive.

I've also had no luck getting my notebook's built-in multi-format card reader to see the dead SDHC either

I am not sure if 51-3 reintroduces the SDHC corruption bug, but this is what just happened to me 2 hours ago and I'm at my wits end trying to recover the card.