We have traced the problem to being USB-related. We have similar images being built for iPXE as well as USB. This system does not support legacy boot options, so those go out the window immediately.
As for UEFI, PXE images work (but without audio). USB images are the ones giving the kernel panics. The same USB-image DOES work on other systems in our infrastructure. Most of these DO support legacy boot options.
My personal conclusion is, that this is either a legacy USB issue, or simply a hardware support (kernel, BIOS) one. Further actions would include:
- updating the kernel,
- updating iPXE, or
- updating the BIOS.
However, these were obviously some of the first things we already tried. I’ll keep this issue open and try newer kernels or BIOS firmware as they come out.