Its been around 4 month that i bought Samsung Galaxy book 4 pro. in this time, there was a BIOS updated 2 month prior, and i was facing same problem.

i.e. when was about to Update BIOS, it just stopped stating, that the Battery should be more than 80% or laptop should be plugged in. and i contacted to samsung team, and they suggested me to factory reset the laptop, and i did it, then i was able to update.

and now there is one bios update, but when i was about to update, same same problem is occurring. 

what should i do now, buying a £1000+ laptop and to update the BIOS, i have to factory reset my laptop. what a experience.