tests/test-admin-deploy-uboot.sh fails on s390x: sysroot/boot/uEnv.txt: No such file or directory

[smcv]

Another test failure on Debian's s390x port. If ostree is treating s390x as a "first class citizen" with its own bootloader-specific code paths, perhaps someone in Red Hat/IBM could set up CI to run its build-time tests on that architecture, so that it isn't always me reporting the test failures?

Relevant-looking part of the log, running build-time tests as non-root in a Debian unstable s390x chroot on a ssh-accessible s390x, which is the only way I can test on this architecture:

+ ostree --repo=testos-repo commit --tree=dir=osdata/ -b testos/buildmain/x86_64-runtime
+ ostree admin upgrade --os=testos
+ assert_file_has_content sysroot/boot/uEnv.txt loadfdt=
+ fpath=sysroot/boot/uEnv.txt
+ shift
+ for re in "$@"
+ grep -q -e loadfdt= sysroot/boot/uEnv.txt
grep: sysroot/boot/uEnv.txt: No such file or directory
+ _fatal_print_file sysroot/boot/uEnv.txt 'File '\''sysroot/boot/uEnv.txt'\'' doesn'\''t match regexp '\''loadfdt='\'''
+ file=sysroot/boot/uEnv.txt
+ shift
+ ls -al sysroot/boot/uEnv.txt
lrwxrwxrwx 1 smcv smcv 15 Oct 26 10:18 sysroot/boot/uEnv.txt -> loader/uEnv.txt
+ sed -e 's/^/# /'
/home/smcv/ostree/tests/libtest-core.sh: line 92: sysroot/boot/uEnv.txt: No such file or directory

test-suite.log