I updated my FOG version from 1.5.7 to 1.5.9 yesterday. FOG is running on CentOS Linux release 7.8.2003. The upgrade completed without issue. Now, computers will boot to the FOG menu, but when any option is selected, the computer reboots.
With the HP Elitebook 840 G3 laptops, after selecting any FOG menu option, it shows
bzImage_5.6.18 . . . ok
init.xz
It then just reboots with no further messages
With the Dell Latitude 5410, any FOG menu option results in the following:
bzImage_5.6.18 . . . ok
Could not select: Exec format error (http://ipxe.org/2e008081)
Could not boot: Exec format error (http://ipxe.org/2e008081)
Could not boot: Exec format error (http://ipxe.org/2e008081)
Chainloading failed, hit 's' for the iPXE shell; reboot in 10 seconds
I tested with multiple computers of each model, including several that we successfully imaged prior to the upgrade.