This is with reference to all those who have been reporting SD Card not being detected after multiple WP7 trials on their HD2.
As mentioned in the list of phones supported (That detect the card, ) Nokia are the best as per my trials.
I too tried sandisk class4 8GB and Sandisk Classs 2 8GB for WP7.
Both times when I was trying to move forward towards 7720, either the update failed or communcation got disrupted making my phone go to recovery console.
Here are the stpes to recover the card whatever happens.
Note: Nokia 5233 (Mobile I used to recover my card) Provides hotswap support for microsd card
1. For safer operation, select Storage memory and click remove card (In 5233 Menu)
2. Remove existing card, and insert the WP7 Bricked SDCard
3. It will show 'Type password to Unlock the card'
4. Cancel that and go to File Explorer and select the card and say Open.
5. After it opens, From the options menu, select 'Card Options>Format Card', Dont select unlock or anything, its not required.
6. If its Class 2 card it will take around 40 seconds to format (8GB).
7. If its Class 4 card it will take around 8 seconds to format (8GB).
Now close file explorer, and open file explorer again to check the card size.
Click Remove card and remove the card.
No need of partition manager,Linux, zero fill formatting, killdisk etc which is real headache.
All it needs is a Friend (Who has Nokia mobile that supports microsdcard).