I just updated the 998. I used my Schumacher PC-6 power inverter and the extra power cord I bought for the unit last winter. I unhooked the cord collecter and the ethernet cable. I have updated without unhooking the GPS receiver with no issues but that was before I added i-Pilot link to the system. All is well.
I bought the inverter last winter to keep the units capabilities fresh in my mind over the long winters we have here in Iowa. I used it when I updated the i-Pilot lin remote,controller etc., when I first added the link system.
Thanks for the feedback fellas!