There are reports that the recent busybox 1.34.0 upgrade breaks starting Sxmo. Users of Sxmo are advised to hold off on upgrading for now.
Update
This issue was caused by a bug in busybox, which has been resolved. The fix is
in busybox-1.34.0-r2, found in Alpine Linux Edge.
Related: - 12960#aports - busybox mailing list thread