Giovanni Grieco

OS research page

info giovanni.grc96 AT gmail DOT com

Upgrading my CPU microcode // Dec 9 2017

Today I found via dmesg that I should upgrade my CPU microcode on Apple iMac 12,2. I have Fedora 27 and this is what I did to fix the problem:

# dnf install microcode_ctl
# dracut --regenerate-all --force

The first command downloads, hopefully, the latest Intel ucode and stores them in /lib/firmware/intel-ucode. Otherwise, it should be freely available at Intel Download Center.
Next, the microcode Linux driver is available via initramfs, so we need to rebuild it via dracut.
Finally reboot and that's it! Enjoy!

Fixing rhbz1497559 // Dec 8 2017

I think that rhbz1497559 affects lots of PCs. This bug happens especially when the OS is loaded via EFI but with Secure boot disabled. Apple computers have this problem and I found that Secure boot is disabled in both iMac 12,2 and MacBookPro 12,2.

This bug should be resolved with Hans' kernel but the patches, specifically

0001-Make-get_cert_list-not-complain-about-cert-lists-tha.patch
0002-Add-efi_status_to_str-and-rework-efi_status_to_err.patch
0003-Make-get_cert_list-use-efi_status_to_str-to-print-er.patch

didn't get to the latest stable kernel (as of 4.13.16-302.fc27.x86_64). Why? I don't know, but I hope they will eventually come.

Just for testing purposes, I have uploaded the patched kernel in /rhbz1497559. Happy testing!