Currently I have a ROM-DOS 7.10 SUV environment installed on a physical PC as a multiboot option. While it's usable, I noticed some caveats:

- For some reasons, only the first two disks/partitions (C: and D:) are accessible. I cannot access other partitions. However, both ROM-DOS' and FreeDOS' FDISK could see all my disks and partitions correctly with no errors or warnings.
- None of the UMB managers I used (UMBPCI or JEMM386) can enable UMB on this DOS variant, despite they load without any apparent error (EMS appear to be functioning, though).
- The initial available free conventional memory in ROM-DOS is much less compared to others, mostly due to the fact that it doesn't have HMA support.
- Also, when using FreeDOS MEM with /C, in my system's case there's a used block of about 64KB of memory with a garbage name. Not sure what it might be.
- FreeDOS' FDAPM can be used with ROM-DOS. However, FDAPM behaves as if it was running on a very ancient computer, slowly printing out characters one by one, though the overall speed is okay. This only happens with ROM-DOS, though. On FreeDOS or MS-DOS FDAPM behaves perfectly fine. Note that this slow character output behavior only applies to FDAPM itself. Other programs can still output properly even after loading FDAPM.

Does anyone else have experience with this DOS variant? While ROM-DOS does have out-of-box LFN support, the issues I'm facing kind of limited its usefulness compared to other DOS variants.