3GS + Old Bootrom - always able to downgrade baseband?
I just want to ask if I have an original model 3GS (old bootrom - 359.3) with any given version of the firmware (lets say 4.3.2) and have already upgraded to the latest baseband, can I always use the bootrom exploit to downgrade my baseband and firmware to an unlockable iteration (no matter what security measures apple adds in the meantime)?
I don't quite understand the relationship between the shsh files (which seem to be per OS version), the baseband and the bootrom. Is it possible that I will be left with a phone that can not be unlocked or will it ALWAYS be possible via the bootrom exploit?
For the record, I currently have 4.3 installed (non-jailbroken). I jailbroke 4.2.1 in the past and saved my .shsh files from Cydia without really knowing what it means.
The most important thing for me is to enable the phone to be unlocked in the future as I plan to move to a different country and I love my 3GS and wish to continue using it in a PAYG plan.