My O.G. Mavics still fly perfectly! You can find batteries on Ebay for them....If you have the old Batteries KEEP THEM!! there are folks out there that can build you new ones!
Make sure to update it and get yourself an R.I.D. module to strap to...
Find some batteries if needed and turn it on.
Update???? Was it working well when parked????
Updates can always wait until some research has been accomplished.
Thats how I discharge..With the Air2s, DJI included a little adapter that fits on the battery and lets you plug a usb device into it. I charge my phone and anything else with them to get back down to 60.