Re: [gentoo-user] UEFI is teh SNAFU!

[Mick]

On Monday 30 Jan 2017 10:56:09 Alan Grimes wrote:
> I had to reboot my system again due to video driver update.
>
> I had set up a new build of my kernel in a UEFI partition. The
> BIOS/firmware seemed to be happy with the location.

What made you reach this conclusion?


> The machine stops stone cold dead the instant the firmware tries to
> transfer control to the new kernel.
>
> I found a switch in the debugging menu which enables the EFI console
> output. Why does this option exist? I mean why is it possible to compile
> a kernel that doesn't use every possible method to communicate with the
> user?

If you are talking about a menu in the kernel configuration, this is because if 
your kernel boots without problem you do not need all this I/O impacting your 
system, or filling up your drive.  In addition, there are people who build 
minimalistic kernels for embedded systems with very limited storage/CPU/RAM 
resources.


> Well, anyway, even with this selected, it still stops stone cold dead
> without producing any output at all. I could turn on some more debugging
> options, but they seem more hardcore than what I'm trying to do...
> (simply boot!!!!!)

It may be that the EFI firmware is not happy with your kernel, tries to boot 
it, but it can't.  I'd try two things:

1. Build a genkernel but make it EFI compatible, then copy it over into the 
EFI partition and run efibootmgr with  the requisite options and paths to point 
the EFI firmware to it.

2. Build and install rEFInd and point the EFI to that.

If you have a kernel problem step 1 above may fix it.  If not, step 1 will 
prove you can boot from the EFI partition (if only by just launching the 
rEFInd boot manager menu).  Then you can make some progress by booting a 
LiveCD with EFI on it and copying the working kernel configuration as a starter 
for ten to build your own kernel with.
-- 
Regards,
Mick