GEOS 128 REU Autoboot Mysteries Unraveled

How can the Commodore 128 boot into GEOS without a cartridge or disk?

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00:00 Introduction
00:26 GEOS128 Autoboot
01:14 REU Capabilities
03:56 The Experiment
08:19 How C128 Cartridges Work
10:50 Hints in the Manual
11:48 C128 Machine Language Monitor
14:25 Will it Boot..?
15:45 System Vectors
18:22 MMU Configuration Register
21:28 Putting it all Together
24:08 Comparing the VICE .reu Dump
28:40 Notes from the Future
29:31 "128 RBOOT"
30:17 Conclusion