I've came up with two trains of thought for you, both of them sorta pulled out of thin air, but still worth looking into:
Originally Posted by gameoffuture
ONE: - The way profiles worked was changed sometime after 2.x was released but before 3.x came out. I'm wondering if this change combined with your unique situation - having two different devices with their own imei, own s/n and own palm s/n tokens, then switching boards ???
- Curious, were both devices AT&T Pre 3's or was one an AT&T Pre 3 and the other an EU Pre 3 ... I'm leading you towards trying Impostah if you haven't got the device working yet.
- You're going to hate this one -> put it back together as it was with the bad PCB that wouldnt recognize your SIM. Then use show properties to nab the tokens all of them, in one grab and just the modem swap tokens in another grab. Then disassemble and reassemble as the semi-working device you have right now.
Then get show properties on to the device again and grab both token files.
Do a stare and compare
Consult with Rod Whitby, sharing the specific differences in Token files. Rod will know if there's any chance they could be the cause of y our troubles. Ignore any that are ruled out, but note the ones Rod indicates may play a role, if any.
If there are tokens Rod points out as suspect, you'll need to follow the meta-doctor process to change those tokens on your semi-working device, then try to activate from scratch all over again once finished.
About the thin air, I'm a Denver Broncos fan, what can I say!
EDIT: Addendum: I've swapped AT&T Pre 3 comms boards back and forth a couple of times and it has worked without any problems, although the devices would assume each others profile identities as expected, they both worked fine after doctoring. I'm thinking this has more to do with your pcb swap then the comms boards ....