Thanks for all the replies. In my case, I’m using a modified engine based on 4.20. Perhaps something got broken in the 4.20 build I’ve got since the build tools for remote building iOS seem very wrong – they’re trying to push Windows paths onto the remote Mac for compiling/linking. After a lot of debugging and hacking around the pathing issues, I ran out of time to pursue it further – but I did get it all the way to the linking step.