I have figured out the issue. I was looking in the wrong place in BIOS for the secure boot setting which was on. Turning off secure boot fixed the process which runs perfectly now.

Hello everyone,

I’m hoping someone has seen this before. I’m at the point where I believe I’ve ruled out the common server-side issues.

Environment
FOG 1.5.10
CentOS 7.9
Apache/httpd
ISC DHCP
HTTP boot
Server IP: 10.29.33.2
Target hardware:

28 × MSI PRO B760M-P DDR4 desktops (MS-7E02)
Intel 13th Gen
Realtek NIC
UEFI boot
These same desktops were successfully imaged from this FOG server last year. The major change this year is that the master image was captured from a different teacher computer.

Failure
PXE boot proceeds normally:

iPXE starts
default.ipxe loads
boot.php loads
bzImage… ok
Could not select: Exec format error
https://ipxe.org/2e008081

The system never reaches FOS Linux or Partclone.

Things already verified
Apache working
boot.php generates correctly
default.ipxe looks normal
init.xz present
bzImage downloads successfully
SHA256 checksum verified
HTTP Content-Length matches file size
Downloaded kernel matches server copy exactly
Rebooted server
Verified httpd, dhcpd, database services are running
Tried both current kernel and archived 5.15 kernel

Manual iPXE testing:

imgfree
imgfetch http://10.29.33.2/fog/service/ipxe/bzImage
imgstat
imgexec bzImage

Kernel downloads completely (~10.7 MB), but imgexec immediately returns:

Exec format error

Question
Has anyone seen an EFI/iPXE compatibility issue with:

MSI PRO B760M-P DDR4
13th Gen Intel
FOG 1.5.10
that causes Exec format error immediately after downloading the Linux kernel?

Are there newer recommended iPXE binaries or known BIOS settings that resolve this?

Any ideas would be greatly appreciated.