Thanks. I'll open a report for grub2.
According to the docs, dis_ucode_ldr is x86 only (arch/x86/kernel/cpu/microcode/core.c), so my guess is that it will be ignored for other architectures. According to the kernel code, dis_ucode_ldr works for both AMD and Intel.
I have some time tomorrow on test this on a ARM device.
Jeroen
On Wed, Jun 5, 2019 at 7:49 PM Tyler Hicks <tyhicks@canonical.com> wrote:
On 2019-06-05 10:03:06, Jeroen Bobbeldijk wrote:
> Hi,
>
> Due to some recent problems with a microcode update which broke booting of
> some laptops I suggest adding "dis_ucode_ldr" to recovery mode boot options
> to allow booting after a bad microcode update.
>
> See the following topics that describe the problems:
> - https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1829620
> - https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/issues/1
>
> When such problems occur it's very hard to see that the microcode loading
> is the issue, the booting just hangs at the purple screen, even removing
> "quiet splash" will not show the error.
I really like this idea. Thanks for mentioning it.
Please open a bug report here:
https://bugs.launchpad.net/ubuntu/+source/grub2/+filebug
We'll need to double check that dis_ucode_ldr works as expected across
all architectures. Otherwise, I can't think of any other technical
blockers to doing this.
Tyler
>
> Kind regards,
>
> Jeroen
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