Subtle bug: "update Mplayer-nodeps" fails with "No match found in tc directory". I think this happens because the second grep in the pipeline here
APP="$(busybox find ${A}.tc* | busybox grep -v .dep | busybox grep -v .txt)" &>/dev/null
matches the substring "dep" in the extension's name, leading to the variable $APP getting assigned the null string. Some tuning of those grep commands appears to be required. (But hey, update worked on everything else! I'm still grateful!)
[This was update version 2.6, but I copied the offending line of script from the latest version, so I'm confident that the problem is still worth fixing.]