Previously, there were bare "return;" statements in some places, even though main() was declared as returning int. This is disallowed by C99 and later, and ORCA/C now complains about it when using full lint checks.
The basic approach is just to see if GS/OS can understand the disk (i.e. if a VolumeGS call succeeds), and if not switch the order. We currently start with ProDOS order, then switch to DOS order if necessary. This is only currently done for 140k images.
Stephen Heumann