Hi Everyone

I have a 1.1.2 jailbroken:

1. before I bought it, so I don't know what the original sim is, not mine anyway so will I still be able to do do a dowgrade/upgrade?

2. You may now be wondering, why do you need to do this when it is already jailbroken, well I have no installer.app and I tried to SSH it but it won't work on 1.1.2, just bounces you out to the main menu. I was told to just SSH apps to my phone and installer.app is crap and will brick the phone? But SSHing apps to the phone is tedious and doesn't help me find apps like installer will, what do you guys suggest? Should I go through this downgrade to get installer.app working on 1.1.1 then upgrade firmware?

3. My phone is unlocked without use of turbosim etc. just put any sim and it works, I believe (not sure) this was done by opening the phone and doing something, is it possible this firmware downgrade/upgrade will lock the phone?

Three important questions for me, I would be indebted to someone if they could set me straight.