Dear Greg oire,
1. Why would you downgrade?
The version you should get on your PRO+ is 2.0.0.B
Battery life is fine in that version. Actually the best I came across.
2. If you have no experience (I haden't either) please go trough the wiki:
https://wiki.mobileread.com/wiki/Ener...roubleshooting
3. When my ereader PRO+ freeses it usualy helps to plug it in the charger and the unplug. Somtimes some button pressing was involved.
4. Updating to 2.0.0B: mine worked doing it the regualar way. But on the wiki is also an alternative way using a flash card.
Hope this helps, kind of understand your problem. Been there...
:-)