Edit - Conclusion
It seems that some older computers can load extensions from a usb drive, and others can't. If you use an older computer, you can try, to see if yours can.
The original post.
This issue has been raised on another topic. So it would be interesting to hear from others.
We know extensions can be loaded from a usb drive during start up on a newer computer with bios support for usb drives.
For those who have an older computer without bios support for usb drives, can your computer load extensions from a usb drive during startup?
A simple way to test this is as follows:
Copy your entire tce directory to a usb drive. You can leave the original as it is.
There is no need to modify your existing installation, except for boot options.
Create another entry in Grub or other bootloader. Change the tce directory to the usb drive and add waitusb=10. So, for example, you may have tce=sda1 waitusb=10. If it does not work, you may try a number greater than 10.
Connect the usb drive to the computer and boot.
Does your computer load the extensions from the usb drive?
Tell us a bit about the type of computer, and what boot loader you are using.
You can then remove the usb drive, and delete the Grub or other bootloader entry, to return your installation to how it was before doing this.
I repeat, only those who have an older computer without bios support for usb drives.
This can also be done running Tiny Core from a CD.
I am interested in hearing from those who actually try this. Not those who speculate about what should happen in theory.