Issues when rebooting after booting over ipxe on kernel 6.1 and above on new Dell servers

[cyberflow]

After booting through the network via ipxe into a kernel 6.1 or higher (efi mode), the system hangs at reboot.
Last kernel messages:

[ 380.946406] systemd-shutdown[1]: Syncing filesystems and block devices.

[ 381.025622] systemd-shutdown[1]: Rebooting.

[ 381.075792] kvm: exiting hardware virtualization

[ 381.313655] ACPI: PM: Preparing to enter system sleep state S5

Tested on ipxe versions:

iPXE 1.0.0+git-20190125.36a4c85-5.1
iPXE 1.21.1+ (g8b146)

Also reprodusible with snponly.ipxe
Issue does'not appear on ipxe + kernel 6.0, using syslinux + kernel 6.1 or local boot of 6.1

Network card: Broadcom Adv. Dual 10GBASE-T Ethernet [14e4:16d8]
chassis: Dell PowerEdge R650xs

[NiKiZe]

Will you be willing to use git bisect to find the commit where this started being an issue. For a guide see https://ipxe.org/howto/bisect

It will require you to build and test a couple of different commits until you find where it breaks, when you start the process you will be shown a gustimate of number of builds you will need to test.