- The problem stems from this commit.
- While the comment in the commit is correct, the problem is that U-Boot has not supported this syntax for very long, so it still breaks on older U-Boot forks.
- Strictly speaking, it is libubootenv which broke this, not us.
- Fix libubootenv so that it supports variable value syntax, in addition to variable=value.
- Submit upstream.
- While waiting for acceptance, submit to meta-mender/master and meta-mender/dunfell as a libubootenv.bbappend patch.
- Revert the Mender client commit.
Backup fix (more hacky, less desirable):
- Adapt Mender client so that it first writes a dummy variable using the new syntax, checks that to see if it can read it back, and then uses that to decide which syntax to use.