I just jailbroke (I think) my 4G iPod Touch (4.2.1). I'm able to do the battery percentage thing, but Cydia has a blank icon and whenever I click on it a window tries to open up but quickly force closes. Any ideas?
Go run red snow and on the check screen unselect install cydia and battery % and enable just loading tetherd. Everytime you reboot you need to redo this until the untetherd version is released and it will not require a restore.