The recently released Ubuntu 21.04, is the latest version of the popular Linux distribution and with the latest release we see Wayland arrive as the default display server. But it seems that those wishing to upgrade from a previous release, for example 20.04 / 20.10 are unable to. According to OMG! Ubuntu! there is a bug which is preventing users from updating to the latest release.

The problem seems to be in shim, the bootloader which handles the secure boot process for the OS. Users running the wrong version of their EFI – an early one – can see their PC fail to boot after the upgrade. A new version of shim is on the way to fix the issue, but users who are sure their hardware is new enough to sidestep the problem can manually force an upgrade at their own risk from the command line. 

“Due to the severity of the issue we shouldn’t be encouraging people to upgrade at this point in time,” wrote Canonical software engineer Brian Murray in a post to the Ubuntu Developer mailing list. “After we have a new version of shim signed will make it available in Ubuntu 21.04 and then enable upgrades.”

The exact nature of the hardware likely to fail is still unclear. We reached out to Canonical software engineer Dave Jones on Twitter, who suggested modern machines would be unaffected but older machines such as a ThinkPad 420 from 2011 and a MacBook Air from 2012 were affected by the bug.

Codenamed “Hirsute Hippo”, Ubuntu 21.04 brings support for Wayland display server, with Xorg still available for those that need it. Native Active Directory integration and a performance-optimized certified Microsoft SQL Server are new features for this release.