Ext GPS worked for me on an iPad 1. using an coPilot bluetooth gps sender. Cost $12 off an UK Ebay site 1 year ago.
Ill recharge it and see if I can find the settings. Dont remember adding lines unless it was for the port and baud in sys.txt.
Dont hold yourbreath though...havnt used it for a while as I put iGO world (Primo) on my iPhone 4s after jailbreaking it.