Dang, I've been looking at too many different files. Now that you mention about the s3c8asm file, I do recall reading that before. It just didn't sink in to the proper portion of my memory bank. Time for me to RTFRM again.
Your blink testing protocol/upgrade worked again as it was supposed to, with the 3 and 4 transposed. Volume, mute, channel all blinked the appropriate number of times.
I changed the line in the 1800 protocol you suggested. I assembled the asm file and then merged the hex file with the beta 4 extender in IR. After upload the behavior is the same as before, except that any key will activate the extender. The volume buttons still do that alternating 4 blink/no response sequence as before. It's still only the volume or mute that does that, though. As far as funny LED behavior, here goes.
There are 9 LEDs, one under each device button (both real and fake). Unextended, the light under the active device blinks with each key press that is part of that device key set or punch thru. I believe there are several keys in addition to volume that are punched through to Audio by default. The device button lights for both the real device buttons and the fake ones.
Code setting procedure on the remote is holding the desired device button down until all of the programmable device buttons light in sequence:
CATV, AM/FM, TV, VCR1, VCR2, CATV, AM/FM, TV, VCR1, VCR2,
The desired button then remains lit until a code is entered. A good code is acknowledged by 3 blinks. There is a slight delay (0.5s?) between the press of the last key and the acknowledgement.
All of the device buttons (real and fake) remain lit when held down until the sequence begins (real only). The exception to this is the TV button, which only blinks on then back off until the sequence begins.
The only other quirk in unextended mode is that the record button only lights the LED on the second press when in VCR mode. I tried that with a couple of setup codes. Pressing another key after the first press of the record button resets it to a non-pressed state (i.e. you still have to press twice for a blink)
Immediately following an extender upload, pressing any real device button except TV gives the light sequence CATV, AM/FM, TV etc. A code may be entered after the sequence without loading the extender. After either code entry or press of a non-numeric key, the next press of a number, volume, or channel loads the extender. The previously hit device key does the 4 blink pattern and all ensuing key presses in the Cable keyset light that button.
I know this is pretty verbose, but I wanted to give you all the information I had.
Thanks!
-Josh