Who told you that you cannot dual boot DOS 6.x or Win 3.1x with Windows 95 OSR2 version? I found the following from Microsoft Newsgroup. It's worth sharing it. I haven't tested by myself because I have FAT32 installed. But if you a hacker or equivalent, you should try it once with your own risk.
Before continuing, I should write a statement. I am NOT responsible for any damage you may experience.
I've been running this for a week now and after a successful testing period, feel it's time to publish.
It is said, and documented, that OSR2 will not perform a Dual-boot to DOS6.x. If you are running a FAT16 partitioned disk, it is possible, but not on FAT32 - at least I haven't tested it.
I had done some retro-fits to Dual-boot on other machines with OSR1 so I decided to see what could really happen with OSR2 and why it won't do a Dual-boot. It hangs part way through the boot process after coming out of a successful boot to DOS6.x and then trying to restart. Looking at the root, I found IO.SYS gone! When DOS7 goes to rename the files, it deletes IO.SYS instead of renaming it to IO.W40 when it renames all of the other files.
After an evening of working through various methods using rename/copy batch files, etc. that worked but were were less than elegant, I found a method that is moderately simple.
All that really needs to be done is to pre-create an IO.W40 file and store it on the disk. If you are comfortable with commandline operation, it's safer to boot to a command prompt only (W95 not running) to perform this operation.
Add the DOS6.x MSOS.SYS, IO.SYS, AUTOEXEC.BAT, CONFIG.SYS to root as *.DOS. Unset hidden, system, read only attributes for W95 MSDOS.SYS and store a copy. Edit the original W95 MSDOS.SYS to add in the boot menu commands. Unset hidden, system, read only attributes for IO.SYS. Copy the W95 IO.SYS (~209K) to IO.W40. Set the hidden, system, read-only attributes when you are finished for all. Reboot to W95 "Normal" to certify that it is happy. Shutdown choosing "Restart the computer". Select "Previous version of MS-DOS".
When in DOS6.x mode, you will see the other files properly renamed to *.W40, the MSDOS.DOS v6.x and other files are properly renamed to *.sys & .bat but IO.SYS *remains* as the W95B version with IO.DOS sitting on the drive unused and untouched, as does IO.W40 when in W95. They are only there to hold a place and copy from during restart. DOS6.x runs happily on the W95 version of IO.SYS. When you close and restart it all works. MS-DOS Mode is unaffected.
Disclamers and Cautions:***************************************************** When doing this BE SURE to have a certified boot floppy for *both* OS's that WORK in case you get into trouble and/or need to refresh some files.
During one boot, I hit Pause to read the POST screen just a bit too late and caught the rename scheme in mid-stream. Performing a manual rename restored the startup succesfully.
Upon checking the drives just now... IO.W40 was GONE! and I've been rebooting all day. :\ Perhaps it only needs to be seen once. I put it back just in case from the stored copy and will watch it for a few days to see what it does.
[YMMV, Don't try this without proper supervision, No Warranties are expressed or implied, All bets are off.] But have fun with it anyway.