My USB drive was formatted as FAT(default) so I reformatted it to FAT32. I extracted the single head boot file on the USB drive. Turned on the machine, it shows "checking RAM" then "DiskBios 1.7 992k", then "insert boot disk". I put the usb drive in and press enter, it shows "trying network", then flashes back & forth between "DiskBios 1.7 992 K & unit 01" then finally says "insert book disk".
I have power to the drive unit (green light & red 000). I have tried selecting 000, 001, 010, all with no effect.
I have also tried copying the boot files from the floppy disk (they have different names "edsapp9a.rsa, edsapp9b.rsa, edsapp9c.rsa, edsapp99.rsa" then what is in the one I downloaded from here), with the same results.
I don't know what else to try.

Thank you for any suggestions.