Hi all,
I realize there is some confusion about how long it will take to complete the firmware update.
I was able to complete the firmware Update for a mk3 61 on a Windows 10 Machine, but it took more than 2 hours. I am not exaggerating. I started the firmware-update yesterday in the late evening. After 2 hours, the update was still not done, so I went to bed. This morning I returned to the mk3 expecting it to be still running the update, but it actually did finish the firmware-update while I was asleep.
So in short, the update took somewhere between 2 to 7 hours to finish, but it DID finish. I really hope this helps!