These log message from com.apple.FSKit, category default, seem relevant. Notably, I don't see any logs from my code, so although it claims that the probe failed, it's not because of my code. Successful dynamic cast of resource to bd. Got fd 3 readFirstSectorAndLog reading from 3 got rv 512 error (null) Successful read, first characters 4c4b:6000 Returning (null) FSModule dev.steve.MFSLives.MFS probe: returned Error Domain=NSPOSIXErrorDomain Code=22 "Invalid argument"

So I tried deleting the first few bytes as you suggested, but hdiutil still fails without using diskimage-class=CRawDiskImage. If I add that argument and then try to run mount, it still fails, but I seem to be getting farther into launching my extension now, although it still isn't actually running any of my code.

I double checked to make sure I wasn't running hdituil with sudo, and unfortunately it's still not working for me. Thanks for your suggestion though 🙂

I double checked to make sure I wasn't running hdituil with sudo, and unfortunately it's still not working for me. Thanks for your suggestion though 🙂

Thanks for your suggestion. I double checked, and unfortunately it's still not working for me.