1. ALMOST no problems. When you flash ROMs, it essentially wipes out the previous ROM. However, the bigger problem is the SD card. If you use Apps2SD in 2.1, you need a Linux ext partition on the memory card. However, 2.2 does not work properly with this partition, since it uses the regular FAT32 partition for storing apps. So if you switch between, you might need to delete the old ext partition if you move to 2.2.
Okay... this part gives me some heartburn. I'm not sure how partition and all that. Frankly, I've heard a lot about Apps2SD, but I'm not sure what it is. Do I have to use it?
The two ROM's I'm most intriqued by are xtr 3.0.3 and KaosFroyo v29 or v30. The main reason I'd like to go to Froyo is to make my Eris a Hotspot. I don't think I can do that on xtr, right?
Sounds like I should dl Titanium Backup for all my setting and data. I'm assuming this thing is pretty intuitive?
Thanks for the help guys. I'm glad to see other non-rooters jumping on and getting some info out of this thread too.
Looking for something like the Rooting for Dummies thread that EU1 put together. That thing is just awesome.