It’s a joke between myself and friends or myself and coworkers that I can always recall random facts at odd points of time and help them get out of a sticky situation. One thing I get called on for often is how to make a DOS boot disk, with the difficulty of having to use the boot disk for a firmware load, so it has to be lean and mean. That said, here are the files you can remove from your boot disk as long as you are only loading firmware/drivers/doing low level stuff:

Delete all files dealing with MOUSE. There should be a Mouse.COM, and a few others. Delete. Get rid of QBasic.exe and QBasic.hlp. You won’t be programming any QBasic stuff today. Scandisk and chkdsk are usually both on there, might leave one, but if this is solely for a driver load, kill both. Also, look for any .hlp files. If you’re still making a boot disk in this day and age, you’re far from needing “help”. That usually clears half of the disk or more. After that, start nixing the CD*.sys files. And if you still need space after that, complain to the manufacturer that what they are trying to have you do is impossible.