We've had working tboot configs on many computers with kernels going back since Linux kernel 3.x. However now starting with 6.8, tboot hangs if we boot on high resolution monitors (5120x2160 @ 120hz) for example. When using kernel 6.8, simply connecting to an older 1920x1080 monitor (with hdmi or displayport) allows the boot to go forward like normal. For some of our high resolution monitor machines, we just connect with HDMI to get it working (which boots the EFI loader at stretched lower resolution...