This hack is impressive -- my 707 just got a lot more interesting.
Unfortunately, I have to add in my observation that Personal Disc Memory is not working for me. Whenever I have a disc in and choose to make an entry, the system seems to work; when I choose "Erase", it finds an entry and erases it. However, when I remove the disc and then reinsert it (regardless of whether or not I'm using battery or AC power), the unit seems to lose the entry. If I go to PERSONAL and choose ERASE, the system blinks "No Entry!" for a couple of seconds before going back to sleep. I wonder if perhaps the memory layout and power usage of the 707 precludes these values from being retained?
It's a relatively minor negative in the midst of a lot of positives. Thank you for the work on this; I would love to hear/see more of the engineering effort that helped uncover these features.
