Thanks to Joe, he provided me plenty of potential clues on how to possibly combine the 4 Toshiba laptop recovery discs that I have. The laptop is one of my oldest computers that I owned, and I wanted to attempt to combine all 4 discs and create a USB recovery.

First of all, I want to say that I only experimented on COPIES of my iso files. This way if I messed anything up, I still had my originals. Please, never tinker and modify any original iso images. Only play around with copies of them.

Second, I used the software called "WinISO" to extract any files for modification, moving, or to insert the files into the first disc.

I realize that Joe pointed his modification clues towards a different PC manufacturer, and what he needed to alter, than the type that I own with the Toshiba. With the Toshiba, the first three discs each had a DATA.INI, and inside of each of those files, it showed roughly a "1 of 4", "2 or 4", and so forth type of scenario. I took and made a change where DATA.INI said that it was a "1 of 1." I did that within the first disc iso.

Another thing that it had in three of the four discs was "ZZImages", and each disc continued forward with additional files. I combined together all of those files within those various ZZimage folders under one roof of the first disc iso.

The fourth (last) disc was the smallest in capacity of all four discs, and it basically seemed to have one quater of the same files of the first disc, except for one file, so I copied that onto the first iso disc file.

After I completed everything, I saved the new and larger iso file, and it appears to be under 12gb large, so I should be able to easily be able to burn the iso file onto a 16gb USB.

I have not attempted to create a bootable USB drive yet, nor do I think that I will be able to test out if what I did worked or not yet. If that day comes to where I will need a recovery, I will try out the USB first. If it doesn't work, then I still have my four recovery discs to fall back on. Also, if that day comes in the future and I need a recovery and the USB fails to work, I will attempt to immediately figure out what went wrong and start over again, while the recovered laptop is fresh again.

Anyway, I figured that I would post what I know, for anyone that has a Toshiba laptop. However, it's always possible that newer (or different) Toshiba models might have done things differently and not used DATA.INI files.