WOW, much basic, but not intuitive in the slightest.
Trying to install Win 10 Pro to M.2 drive. System/MB supports the OS, but noting the difference in steps whether the M.2 drive is seen in BIOS, boot is on UEFI/Legacy/Both, and the NVMe Firmware Source setting for SMC systems.
BIOS Optimized defaults
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%20Boot.jpg?version=2&modificationDate=1655221045996&cacheVersion=1&api=v2&width=333&height=250)
%20Boot-UEFI.jpg?version=1&modificationDate=1655220017705&cacheVersion=1&api=v2&width=333&height=250)
%20Save_and_exit.jpg?version=1&modificationDate=1655220018191&cacheVersion=1&api=v2&width=333&height=250)
Non-UEFI USB Boot Media installation - selecting M.2 drive to install Win10 Pro
Stops here.
UEFI USB Boot Media installation - selecting M.2 drive to install Win10 Pro
Works.
