Hope you find this useful...
An easy2boot USB drive will boot most linux ISO files just by copying over the linux iveCD ISO files.
To add a Win98SE Install ISO, you need to delete all unnecessary folders and rename the ISO file to have the .isoDOS01 file extension.
You can then boot directly from the USB drive and choose the Win98SE ISO from the menu.
For more details see here.
The same principle should work for most DOS-based Install ISOs (as long as you keep the files numbers down by pruning!).
Edited by steve6375, 27 November 2013 - 02:15 PM.