Created an image of the bootable disk already created using OTLPENet.exe, then used an app called “Rufus” to create a bootable flash drive using this iso. Didn’t work… perhaps because the app insisted on NTFS file system? Final lines of error log read:

Failed to add SetupSourceDevice in F:\txtsetup.sif

“BOOTMGR not found” message when tried to boot.

Will probably just get a new external CD drive tomorrow, but the flash drive would be handy to have…