A philosophical question about ISO testing

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Is if fair to try and try again to get the ISO test to pass?  Case in 
point... I installed from a USB flash drive prepared with Unetbootin.  
It started in the UEFI install mode. I had my test machine set to Legacy 
boot and after a couple of attempts got my machine totally hosed as far 
as who is booting what to whom.

I just completed an install from the same image burned to a DVD. 
PERFECT!  It follows the test case exactly. However, it did not provide 
me with a chance to do a UEFI install - perhaps because the PC is set to 
Legacy(?)  I will set it to EUFI and try from the DVD again.

Bottom line... should there be a separate test case for flash drive 
installs? or EUFI installs?

Thanks,

Ken

p.s.  Just started from DVD with the PC set to UEFI.  It started the 
UEFI install which does NOT match the test script.  Should I fail the 
test because the sequence of prompts is not exactly per the script???