Gmail is strugging with sending one or more of my emails, so I've created a new email thread. Basically, AHCI isn't working with part_blk for me. I am running genode (foc_x86_32) on real hardware. With rom_blk, part_blk works fine. With ahci, it freezes. I have found the line of code in part_blk relevant to the freezing to be the following part of partition_table.h:
_session(Driver::driver().session())