Using MX29F1615-10 for bigger KS

[jltursan]

I'm experimenting with this eeprom as its capacitity is four times the standard and it's pin compatible with the Amiga kickstart socket.

I've started with the most basic operation to test the compatibility, I've dumped the working KS3.1 from my A600 and flashed the MX with it repeated four times (the usual trick if you don't want to deal with pullups and such).

Well, it doesn't works, I'm only getting a red screen. Then I've also tried pulling out from the socket pins 1 & 40 and connecting them to GND, this way the chip must work like the original; but no way, red screen.

Do I need something special to make it work?, any positive experiences with this eeprom?, although seems identical, maybe there're electrical differences :angry:

[jltursan]

OMG, do you think that the new ROM is being mapped over RAM?, I'm busted then...

My A600 has indeed 2MB chip and a Furia accelerator; so plenty RAM here :-(

I've never thought about this subject, I'll need to check carefully how it's mapping the RAM right now.

[jltursan]

You can find these from several eBay sellers, I've sourced mine from this one (the offer is really good):

http://www.ebay.es/itm/5pcs-MX29F1615PC-10-MX29F1615-Flash-EPROM-DIP-42-/391516410121?hash=item5b28325109:g:k94AAOSwARZXlv3H

The only drawback is that they have a low number of writes (about one hundred); but usually, if they're not used as a tests bed, you'll never reach the limit :-)

Btw, you're right, my dump was bad, I found a dozen of bytes wrong. No idea if the original kickstart is weaking or my trusty Wellon has cheated me. Using an already well-know dump I was able to create a 2MB image successfully: Cloning the first 512KB four times and byte swapping the result was enough, no need to pulldown pins.