There are reports appearing on the ASC Forums regarding failed installation of Monterey on older Qualifying Apple Computers. In most cases this is related to having a NON Apple Original internal drive ?
The EFI Boot ROM included in Monterey is verifying for Original Apple Drive and if not found , may Balk or fail to upgrade to Monterey.
Reports indicate the EFI BOOT ROM is Required to Flash the Computer and is a requirement for a Successful Monterey Installation.
The workaround is to replace the After Market Drive with an Apple Original then run the Monterey upGrade to the computer. Then, reverse this action by removing the Apple Original Drive for the Samsung Drive and run the Monterey upGrade again.
Because the EFI Boot ROM has been applied to the computer - this may allow the upGrade of Monterey to Samsung Drive to be successful.