Unhappy [Q] Reverting Fujitsu M532 Tablet to ICS

I have a Fujitsu M532 updated to JB. After updating I have lots of problems with Wi-Fi connection.
To fix Wi-Fi problem, I need to root that device, I tried every way suggested here or somewhere in
net with no success.
I think that waiting for an update to 4.2 or 4.3 from fujitsu is just wasting my time.
I want to know is there a way to get back to original ICS stock ROM?

(This is my first post here in XDA, excuse me if I asked a wrong question or asked in wrong forum).