actually you can. I did this update last week and have neither it connected to a bypass or parking brake. I did have trouble though, and how I fixed it was to find a older 512mb thumb drive and I took it to work and used an older PC to format it to FAT32. It automatically wants to format to just FAT select FAT32 and deselect the quick format. This worked for me and then of course only one file at a time installing the SYS file first.
Worked for me.