I have a bit more of information. First off, I've been reading through the interminably
long thread "ATmega1284P: End to End using 1.0 IDE", and there were gazillions of sketch
uploading and other problems over there, fuse settings/whatever. Was anything finally
resolved, or just a bunch of suggestions proferred?
http://arduino.cc/forum/index.php/topic,80483
My bit of information is, I've been uploading good-sized 32KByte sketches to my 1284 by
the bushload, using IDE 1.0 and 1.3, and using both FTDI cable and FTDI Friend, and not
seen even a single glitch.
I do have the 1284, and not the 1284P, chip programmed with the Bobuino variant of
maniacbug's v4.5 optiboot.
Secondly, my board here is a hacked proto typing shield with a lot of soldered wires and
a lot of wirewraps. In fact, the connection to the RX0 pin is a 3" long wirewrap wire
that I have now purposely strung "between" the crystal pins, just to try and inject some
extra noise onto RX0.
So, no low-pass filter on RX0, RX0 signal passing in between crystal pins, large 32KB
sketch, and nary an uploading glitch after several dozen burns. So, all in all, ...
no problema. Maybe the moon here is in its happy phase, or because I'm playing
Mozart. ???