On April 8th 2020 we received reports from users about Clear Linux OS
installations failing to reboot after updating to 32780. This Clear Linux
version included an update to Linux kernel 5.6 which introduced a
configuration `CONFIG_EFI_DISABLE_PCI_DMA` that does not work consistently
with many EFI implementations. Impacted systems do not boot successfully,
getting stuck at the error messages "exit_boot() failed! efi_main()
failed!". This does not appear to impact all systems. To prevent this issue
from impacting more systems, we are pushing an update to revert the
**If you have a system which is experiencing this issue:**
A previous version of the kernel is still available on your system to boot
from and can be used to work around the problem.
1. Reboot the system.
2. Interrupt the bootloader by holding the `SPACE` bar key on the keyboard
after the system POSTS.
3. From the bootloader screen, select a kernel 5.5.x or older using the
arrow keys and hit the `ENTER` key on the keyboard.
**If for any reason a previous kernel is not available for selection:**
1. Highlight the 5.6.x kernel from the bootloader screen.
2. Push `e` on the keyboard to edit the kernel cmdline.
3. Use the right arrow key on the keyboard to reach the end of the line.
4. Add `efi=no_disable_early_pci_dma` and hit the `ENTER` key on the
keyboard to boot with the modified kernel cmdline.
**If you have a running system which has not yet rebooted:**
1. Defer rebooting if possible.
2. Manually run `swupd update` and make sure it updates to 32800 or newer
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