Update 2019-05-21 19:37 EST: My motherboard is on the latest BIOS available, released 2019-03-06, but still has the install problems described below.

Update: I burned the Arch ISO to a CD then tried booting from it, both in UEFI and legacy. Same type of result:

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Original question: I used dd to put this Arch ISO (Version 2019.05.02) on a USB stick, then attempted to boot from it on my desktop computer. When the Arch menu comes up, I choose "Boot Arch Linux (x86_64)." But what follows is a bunch of error messages, then the process just hangs there doing nothing. Here's a pic: enter image description here

The messages start off as "AMD-Vi: Completion-Wait loop timed out"

The messages include "kernel panic."

My motherboard is an MSI B450 Tomahawk with a Ryzen 5 2600 CPU. I've tried booting via UEFI and legacy with the same result.

How do I install Arch Linux?

  • 1
    Not directly answering your question -- does your downloaded ISO match the provided checksum(s) in that linked directory? sha1sum archlinux-2019.05.02-x86_64.iso will give you the SHA1 hash, which should be a86b13e041996942529cd7d51405a87ffbb36caa. May 21, 2019 at 13:17
  • 1
    This looks like one of those bugs with a fix which is good enough to fix the problem, but unfortunately not good enough to be merged into the kernel... May 21, 2019 at 13:27
  • 1
    I would update the BIOS and try a more recent kernel. Another try is enabling legacy mode and disabling AMD SVM, at least during the install phase. May 21, 2019 at 14:34
  • Related: askubuntu.com/questions/1089524/…
    – S.S. Anne
    May 21, 2019 at 21:51
  • 1
    @PeteCooper Checksums match
    – Username
    May 21, 2019 at 23:34

2 Answers 2


Linux Kernel With MSI B450

The kernel fail in this case because of the support of the iommu feature; you can use some specific kernel adjustment (parameter) to fix your booting issue, this video demonstrate how to edit/apply the kernel parameters; here are some possibles solutions, try the different proposed parameters and choose the one that match best your needs. also you may turn off SVE in the bios.

Possible Solutions: Kernel Parameters

  • iommu=off
  • iommu=off and amd_iommu=fullflush
  • amd_iommu=off
  • mem_encrypt=off
  • amdgpu.runpm=0
  • pci=noats

Involved Technology Definition

Kernel Parameters: (aka Boot Options) Kernel command line parameters are parameters that you pass on to the kernel during the boot process to adjust its features or capabilities.

IOMMU: is a memory management unit that basically increase performance and security; additional details can be found here

IOMMU State: on, off or fullflush (detail on the linked article)

mem_encrypt: Add support for Secure Memory Encryption (SME). and defines the memory encryption mask that will be used in subsequent patches to mark pages as encrypted.

amdgpu.runpm=0: disable the graphical power management in the linux kernel (it will be then handled at the hardware/firmware/bios level)

pci=noats: disable PCI Address Translation Services


  • After the install you will need to be very careful on kernel updates

  • Advanced technical users may build their own kernel with this or that patch

Arch Boot Disk:

To apply the parameters to the boot disk, on the boot menu, push "tab" to edit the boot command, hit space (to add a space) then write the parameter for instance "iommu=off" without quotes then hit enter to boot


launchpad, freedesktop, freedesktop, freedesktop, askubuntu, wikipedia, artofcode, archlinux, linuxfoundation, fclose, youtube, youtube

  • From the Arch CD menu, how do I get to the point of editing the kernel? Does my blank SSD even have one? Maybe I’m asking the wrong question...
    – Username
    May 23, 2019 at 13:11
  • @Username on the youtube video i linked it should be explained... basically on the grub menu where you select the boot option normally pressing "e" let you edit the menu and "ctrl+x" to boot after writing the modification youtu.be/BdBnVDF8qvQ?t=141
    – intika
    May 23, 2019 at 13:16
  • I don’t believe I have Grub. I have a blank SSD and anther with Windows 10. My boot option is my CD drive in legacy mode. I tried pressing “e” and “ctrl+x” on the Arch screen but nothing happened.
    – Username
    May 23, 2019 at 14:30
  • @Username boot into your arch cd, push "tab" to edit the boot command, hit space (to add a space) then write the parameter for instance "iommu=off" without quotes then hit enter to boot
    – intika
    May 23, 2019 at 15:06

Add acpi=off or iommu=soft while booting. Both have their disadvantages:


Linux can then detect everything properly (all cores) and I've had zero crashes. The only issue is that it's using software IOMMU which could have a performance penalty because it has to copy all the data of some PCI devices to sub 4G regions.


Alternatively it boots with the kernel option "acpi=off" but only detects a single core/thread.

Resource: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1747463

To add one of these options, press Tab at the screen that says Press [Tab] to edit options and add it at the end of the line that contains initrd=.

Resource: https://www.reddit.com/r/archlinux/comments/9bv2vj/how_to_add_kernel_parameters_to_boot_from/

If that doesn't work, check and see if there are any available BIOS and/or Arch ISO updates. You might have a better chance of getting it to work if/when Arch includes Linux kernel 5 in their images.

Resource: https://askubuntu.com/a/1091191

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