BusyBox, gamekiller (3.11), lucky patcher, Rom Manager, Rom Toolbox work too.
There are so many busybox apps on the playstore, can you give me the name or url of the busybox version you are using ?
* Add to list: Volume up control no longer works when either a headset or an external speaker is plugged into my Nexus 7 (WiFi, 32Gb, 2012)
Do you mean any specific volume up control ?
volume up/down keys and controls in settings->sound->volum...