I see that there is a recovery tool for SPA2102 do you have it for SPA2100, we have some units we may be able to revive
The SPA2100 firmware is attached here: https://www.myciscocommunity.com/message/7915#7915
WRT line2, have you tried resetting the SPA2100?
What happens if you attach a phone to it, does the hook status change?
If you're not using line2, don't concern yourself over its state.
I've attached the recovery tool for you.