For whoever might be interested, finally got some time to put together an iBoot & SecureROM loader for both Binary Ninja and IDA that maps segments (TEXT, CONST, DATA, BSS) correctly.

https://github.com/jonpalmisc/ibis

GitHub - jonpalmisc/ibis: Segment-accurate iBoot/SecureROM loader for Binary Ninja & IDA Pro

Segment-accurate iBoot/SecureROM loader for Binary Ninja & IDA Pro - jonpalmisc/ibis

GitHub
Still a WIP, but should be useful so far. Would also like to look into how microkernel iBoot works some more and see if there's any improvements that can be made there.