FstubCreateDiskRaw is supposed to wipe the MBR when it makes a RAW disk.
Before this fix, that function only cleared the first of the 4 partition entries, so one entry (16 bytes) instead of the whole table (64).
As a consequence, the wiped MBR written back to disk still had entries 2, 3 and 4 sitting there with old data, and those came back as ghost/garbage partitions.