Speaking to your two broad possibilities: (a) incomplete write to the USB and (b) incompatibility between hardware and test environment.
ISO to USB write process
My laptop is running RHEL 7. I downloaded the ISO to that laptop, and ran the suggested dd command to write the ISO to the USB drive. The dd command seemed to finish successfully.
(I thought I had saved my dd output somewhere, but having trouble finding it now.)
As I mentioned in the previous comment, the checksum of the file on my laptop matches. This seems a pretty rock-solid copy process. Note that I did *NOT* pre-format the USB or anything: I just assumed the DD process would destroy whatever was there and write from the beginning.
I'll check with a different USB. I'll also try writing it from the desktop using a different method (other than dd).
Incompatible hardware / exam environment
Bluntly, this seems impossible. The laptop is already running RHEL7! It should be pretty much guaranteed to be compatible.
For the desktop: this is info that I didn't have when I first commented last night). On the desktop where I worked-around the boot issue using grub commands:
- I ran the exam compatibility test last night, and it passed
- Then today Iactually took an exam on it. The environment worked fine. No issues whatsoever: chat with proctor, monitor via webcam, exam loading, VM access, etc etc etc. So that seems to completely rule out compatibility issues on the desktop.
(My actual performance on the exam is another story...)
The success of the exam compatibility test, AND the exam itself, raises doubt about whether the ISO-to-USB copy was bad. How bad could it have been, if everything other than booting worked perfectly? That's a very specific and restrained write failure.
Switching between exam modalities
Switching between modalities can be difficult in the current Covid climate. I live in Maryland; the local testing center has been closed for several months. Reopening date unknown. Travel between states to a different testing facility raises other potential issues.
For some of us, remote testing is by far the most practical method, for the near future. (Which is why you guys rolled it out in the first place!) Not so easy to switch modalities.
And I don't really believe there is an incompatibility issue here. Something else is going on. Does the Sandisk Cruzer protect a partition or some sectors at its beginning? Do the dd did not start where it was supposed to?
Or is there something wrong with the ISO? Doesn't work properly with UEFI systems, or something?
