Yesterday I installed the 1311 maps for my regions on my XC60 T8 at home.
My firmware is about one year old, not the latest, still showing XM expired message on boot.
Because it is seldom driven, I can't install it on road so did some tricks to do it in garage.
- I only drive along west coast so only downloaded 4 regions to USB drive that cover AK to CA, Mountain, and BC Canada. About 6GB total. This probably reduces installation time compared to the entire North America map.
- Start installation from USB drive when you go on a trip of 20 to 30 minutes or longer. So 12V battery probably is charged up, and hybrid battery is used up when get back home.
- After parked in home garage, turn on the car fully, stay in P and parking brake applied. Wait for 1 or 2 minutes and the installation will continue. Leave the key fob in car. Turn off all electronics, head light, DRL, radio. This way the car can't be locked, so close your garage door instead. Read the 12V voltage with a multi-meter or a USB dongle with voltage reading. Map installation will continue. The car can stay in such state for some time between 30 minutes to an hour I think. So check back around 30 minutes to see if it is still on. Check the voltage again to make sure it doesn't go low. In my case it still stays at 14.1V after 30 minutes.
- If the 12V voltage is quite stable, you can leave it like this. Otherwise you should plug in and start charging. I guess after an hour or so the car will shutdown. You can come back and start it again. Anyhow check the 12V voltage every 30 minutes to make sure it is in very good range.
- After some time you'd want to plug-in and charge. You still need to leave the key fob in car, door unlocked, and turn off and on to ACC on position. Charge will continue but Sensus only stays on for less than 10 minutes. So you need to come back every 5 to 6 minutes and do something on Sensus to keep it on. Don't worry if you missed it and it went off. Just switch on to ACC and it will continue after one minute or so.
- If you don't want to do so to keep it awake, just leave the car charging overnight. Next morning you can do it again by turning on the car fully active and staying on for 30 minutes to 1 hour.
So accumulatively you can get at least 2.5 hour for the installation and hopefully it will finish. It took maybe 2 hours for my four regions as I missed a few times and Sensus went off. Maybe this is even enough for the full map but I didn't try it.