GMA 245 Software Update Bug

For historic reasons, the Garmin GMA 245 audio panel in my RV-9A is not on the CANbus, so software has to be updated via SD card. The manual "recommends" a 4GB SD card, but apparently the update won't work with an 8GB card. Ask me how I know. (I think) what made the update work was using a 2GB SD card. (I didn't have a 4GB SD card lying around.)

Although this is not definitive, Garmin tech support agrees with this hypothesis. And it's not unusual for device not to work with SD cards that are "too big."

My guess is that the Garmin looks for a FAT32 formatted card, which is limited to 4 gigs. Could be wrong, but I've seen quite a few embedded systems that don't support the larger sizes that come with NTFS file formats. I know the G3X works with larger size cards, but the audio panel may never have gotten that firmware update.