in trying to see how far reboot to MS-DOS in win9x can be pushed, i've experimented a bit with loading EMM386 via loadsys. this is explicitly said to be possible in the loadsys documentation, provided the /od switch is used, because otherwise it wouldn't accept an .exe file as a device driver. there don't seem to be any issues mentioned with doing this either. it appears to load it fine at first, after some messages about interrupts, and does show the EMS memory after a mem /c. but if i then load mouse.com and mem /c again, the system will hang at a blinking command prompt. interestingly, devload likewise mentions EMS, though using the old emm.sys instead, so clearly at least some people also had this idea.

the other problem with it is, io.sys already contains DOS=HIGH, and putting DOS=HIGH,UMB into config.sys isn't able to override it after already booting to win95. so there would need to be some way to change what io.sys is doing. i think in theory having DOS=HIGH,UMB in io.sys wouldn't hurt anything, because my understanding is it's simply ignored if EMM386 isn't present at boot.

i'm aware BootGUI=0 and loading everything normally via config.sys boot menu is the proper way, but sometimes it's nice to find an alternative. and by the way, i've found the win command to be a bit flaky, for me it stops working at least after rebooting to DOS 2 times.