I just picked up a TRS 80 Model 4p with a nice white chassis. I took a sampler of boot disks that are known to work on a regular Model 4. I thought I would test them on the 4P (it came with no software).
NEW DOS 8
TRS DOS 6.2
DOS Plus 3.5
DOS Plus 3.4
TRS DOS 1.3
When I try them on the 4P, I get the following message:
"Loading ROM Image"
...and then a few seconds later the error message:
"The ROM Image Was Not Found on Drive 0"
EXCEPT when I boot TRS DOS 6.2
The manual indicates that TRSDOS 6 ships with the 4P. It is that simple, you can only boot a 4P with 6.x?
Nope...you need to copy the Model III ROM file from any bootable disk. The 4 P does not come with the Model III ROM installed, you need a diskette with this "ROM" file.
Fortunately in addition to 6.2, I have a utility programs that boot: Copycat 4.1 and a Hyperzap 3.2, Super Utility ! 4/4P
TRS - 80 Model 4 60K System CP/M 2.2 v 1.42 (Montezuma Micro/Misosys)- boots fine
CP/M Plus Dig Research v 1 - (CP/M version 3) - boots fine.
My only other 4P I own has a hard drive, so I never tried to boot with diskettes. The 4P is not 100% compatible with the "4" in that it does not have the Model III ROM installed .