Just in case you need 'em, here's the instructions I followed to do mine. There's about a million different ways of doing this mod, but this one seemed the easiest:
http://aminet.net/docs/hard/a500chip.lha
Man, I almost died last night !
I decided it's time to do the famous 1 MB chipram hack, right ?
So, I pulled out my half broken, for spare parts only rev 6a mbo, followed
the simple instructions, cut the lower trace on JP2 jumper, did the same on JP7A, then took out my soldering iron, and connected the upper and middle connection on JP2. Everything went well.
Connected the bare mbo to psu, 1084 and a fdd, booted into wb 2.1, and voila, 800-ish kb of chipram free, 0 kb other mem. Yeeah ! I'm da man, right ? NOT QUITE !
So, after that, and with a gigtone of confidence, I pulled out my true Amiga, and repeated the above steps in the exact same order. And ... nothing happened. All I got was a blank screen and a flashing keyboard light ! Whaat ?! 5 short flashes, one long, and I think one more then a reboot. Although there was nothing on the screen I could tell Amiga rebooted itself.
At that point I think my heart stopped. Twice !
So, after an hour or two of thinking what could've gone wrong, googlin around trying to find any info on those mind shattering flashes and, in utter despair, I then decided to turn the connections back as they were.
! PRAISE THE LORD ! THANK YOU JESUS ! It worked. Everything was back to normal.
Now, with my hands still shaking, I think I'll reconsider doing this again.
But, why didn't it work the 2nd time ? What do all those flashes mean ?
