[Solved] Upgrading the Old-Fashioned Way on Surface Pro 3

[JamesWilliams]

Tim, that worked! Thank you. I now have r 10637 running on my Prime, so this gives a solution for those of us running Microsoft Surface Pro 3s and 4s.

Some feedback on recovery mode:
To go into recovery mode, with the calculator already on, I had to press the Symb button first and only then the On button. That seems to contradict this link: http://www.hpprime.de/files/composite_fi...y_mode.pdf. I found that if I pressed the On button simultaneously with Symb, or even an instant before, it didn't go into recovery mode.