On the Aircraft Spruce website the FAQ for the GTX 335 says that a software update is in the works for using the 335 as a WAAS source for a G5. According to the Garmin website, they are on version 2.12 now. Does anyone know if the updates allow it to be used as a WAAS source? Can you use the Garmin GTX 335 output RS232 as a certified WAAS GPS source for the G5 installation? The GTX 335 transponder w/ GPS will be able to pass the GPS data directly to the G5 as long as it is running software version 2.10 or later, but per Garmin the software update for the 335 to enable this for certified installations is not yet available.