Problems burning Kickstart

[mfilos]

Not yet

[danko]

Hi,for Amiga 600/1200 uv eprom 27C4001 is compatible?

[Jope]

Originally Posted by danko

Hi,for Amiga 600/1200 uv eprom 27C4001 is compatible?

It is not compatible with the kickstart ROM socket of any production Amiga.

Perhaps I should use this opportunity to repeat that the compatible parts are:

256k:
27c200, mx23c2100
512k:
27c400, mx23c4100

If you're considering ANY other part than those four, it will not be a drop in replacement and it is up to you to look at the datasheets and make a personality module.

[danko]

Ok,i have a Hitachi HN27C4000,i just wanted to know if those were compatible.

Many Thanks

[Quagliarulo]

Why do Willem programmers store 16 bit words in Hi/Lo order? I mean, if you have data lines b0...b15, you store the low byte first (b0...b7), then the high byte (b8...b15), don't you?

[ajack]

Originally Posted by danko

Hi,for Amiga 600/1200 uv eprom 27C4001 is compatible?

I believe that is a 32-pin part, you should use 27C4002 which is a 40-pin part. Correct me if I'm wrong...

[chaos]

Originally Posted by Quagliarulo

Why do Willem programmers store 16 bit words in Hi/Lo order? I mean, if you have data lines b0...b15, you store the low byte first (b0...b7), then the high byte (b8...b15), don't you?

Depends on the endianess of the system.

[Foul]

My Prob : i want to put Kickstart 2.04 in my A500 Boosted to A500+

First was my A500 with Motherboard REV 8.1A Upgraded to A500+ with 1Meg chip ram and Clock added.

I just Burn a 27c400 eprom with Kickstart 2.04 (swapped bytes) and now my Amiga still show a blank screen...

If i put the Original 1.3 ROM, all is fine...

Help !

[FOL]

Originally Posted by Foul

My Prob : i want to put Kickstart 2.04 in my A500 Boosted to A500+

First was my A500 with Motherboard REV 8.1A Upgraded to A500+ with 1Meg chip ram and Clock added.

I just Burn a 27c400 eprom with Kickstart 2.04 (swapped bytes) and now my Amiga still show a blank screen...

If i put the Original 1.3 ROM, all is fine...

Help !

Burning to fast?

[tomse]

don't forget to concatenate the binary file 2 times as the eprom is larger than the file.

the filesize needs to be 1 meg in size for the 27c400

for windows:
copy /b rom.bin+rom.bin newrom.bin

or use the free HxD hexeditor

[Foul]

copy /b rom.bin+rom.bin newrom.bin done but not working it seems to reset in case of showing Kickstart logo

No pin to bend or to connect ???

[tomse]

if you have the bin file from an original rom, you don't need to byteswap it.

do you do a verify after burning the rom?

[Foul]

yes, auto-verify in my GQ4X programmer and i check if all the data are here each time by re-reading the burned eprom... will re recheck this evening... thx

[Foul]

check check re check.. don't want to boot

I already do the same thing for an old A600 and my A1200 without any problem... but this A500(+) is a mystery

edit: just tested with KS 1.2.. and it's working... so why this 2.04 refuse to work ? (md5 is ok : DC10D7BDD1B6F450773DFB558477C230)

Maybe the 1Mb chip hack ??? JP2 JP7 jumper ???

[Solo761]

Originally Posted by tomse

don't forget to concatenate the binary file 2 times as the eprom is larger than the file.

the filesize needs to be 1 meg in size for the 27c400

for windows:
copy /b rom.bin+rom.bin newrom.bin

or use the free HxD hexeditor

1 meg? Isn't 27c400 512x8bit, 256x16bit? I only had to copy /b files when flashing A1200 rom since they're 512kB but splitted in two chips.

Originally Posted by Foul

check check re check.. don't want to boot

I already do the same thing for an old A600 and my A1200 without any problem... but this A500(+) is a mystery

edit: just tested with KS 1.2.. and it's working... so why this 2.04 refuse to work ? (md5 is ok : DC10D7BDD1B6F450773DFB558477C230)

Maybe the 1Mb chip hack ??? JP2 JP7 jumper ???

What's the speed of your 27c400 EPROM? AFAIK A500 is picky when it comes to speed, for some reason if it's slower than 120ns it won't work.

I've read that people had your symptoms when they burned it to 150ns EPROM while that same EPROM worked fine in A2000.

[Foul]

they are 150ns but working well with burned 1.2 and 1.3 kickstart !!!

[ajack]

Originally Posted by Foul

they are 150ns but working well with burned 1.2 and 1.3 kickstart !!!

From what I've read, 1.3 is only 256k in size so it'll accept 150ns parts, but when you burn a 512k chip, needs to be 120ns or faster... if you check it's contents, you can only see the first 256k which is fine for KS 1.3 and below... Please correct me if I'm wrong...

[Foul]

is there another eprom i can try ? 27c800 ? or only 27c400 ? all my 27c400 are 150ns

edit: just tested with a genuine A600 2.05 Kickstart from a friend and it works ! so it's 99% an eprom prob

Must find some 27c400 120ns or faster...

[tomse]

Originally Posted by Solo761

1 meg? Isn't 27c400 512x8bit, 256x16bit? I only had to copy /b files when flashing A1200 rom since they're 512kB but splitted in two chips.

you are so right!, I don't know what I was on, but suspect drinking water from the toilet wasn't such a good idea

[alexh]

AFAIR some (all?) A500's need a jumper wire between two pins (1 & 31) on the EPROM to support 512Kbyte EPROMs.

Without it A17 is floating.

Not sure a Rev8.1A would be affected though.