exxos's Atari, Amiga & retro forum

I have purchased a GVP HC+8 for the A2000, and it’s not happy.
With onboard 8mb, the system works until the Amiga goes to access the 8mb then crashes/resets.

I can boot with no start up sequence and goto sysinfo, i can see the gvpscsi device in 32bit mem so that is a good sign?

With no memory installed, flashy screen from the TF536 and then blinking power light.

I have ran out of time tonight but my next test will be to disable auto boot and put the GVP device driver icon in the Expansion folder and see if activating it later in start up helps....

With v7 ROMs I found mine booted OK TBH (with the A2091) - but... I swapped the bus tranceivers for 74ALS245 on my A2091 to make it happier with all my A2000 boards (and my A4000 board - courtesy of Mr TerribleFire). I did however find it froze the system when I tried to navigate into a folder after opening one of the SCSI drives up. That was when booting from TF536 IDE with A2091 auto boot disabled. It's probably a DMA issue, maybe its doing something dumb like trying to DMA into the ZIII RAM.

GadgetUK164 wrote: 12 Nov 2020 17:53 With v7 ROMs I found mine booted OK TBH (with the A2091) - but... I swapped the bus tranceivers for 74ALS245 on my A2091 to make it happier with all my A2000 boards (and my A4000 board - courtesy of Mr TerribleFire). I did however find it froze the system when I tried to navigate into a folder after opening one of the SCSI drives up. That was when booting from TF536 IDE with A2091 auto boot disabled. It's probably a DMA issue, maybe its doing something dumb like trying to DMA into the ZIII RAM.

In the mountlist for the drive you need to set the memory type to chip,

BufMemType = <Value>


Possible Values: -

0: Any memory
1: Public, any memory, marked as public
2: Chip RAM
4: Fast RAM
256: Local, memory that is persistent
512: 24-bit DMA capable memory

The only values that will work with 32 bit ZIII ram installed in a 16 bit system are 2 and 512.

Thanks again (I do remember you mentioning that before when I raised the issue I think!)! I will have a go at some point once I get this CPC and Neo CD out of the way!

Interesting update here - I fitted 74ALS245's to the Zorro databus side on the rev 6 A2000, and found it boots from IDE, and the SCSI works too! Note: You will have to change the drive ID's of SCSI drive (eg. if you have two DH0, DH1, DH2 etc - these will clash). But, it works perfectly! In programmed IO mode - very slow, but perhaps using the "fix" on AmiNet for use with an A4000 etc, a window in Chip RAM for a buffer probably brings SCSI speed up quite a bit. I've not tried that yet.

In summary - I alread had ALS245's on my A2091 to give better stability with large file copies already. Now have ALS245's on the Zorro databus positions on the A2000 too.

Nice work!

Is that the same rework as mentioned in http://ftp.fau.de/aminet/docs/hard/Amigafix.txt ?

Did you have LS parts in there before?

I never noticed that particular change tbh! I spent ages working on a few A2000 boards here - one of which already has ALS chips. I tried ALS chips as part of a process to work out what was causing issues with the A2091 and long file copies failing (that was ages ago). Fitted the ALS chips to the A2091 and found it was then rock solid stable with those long copies on all 3 A2000 boards and my A4000 board.

But, the 2091 still wouldnt work with the 536 for me. Until I swapped out the LS chips for ALS on the 2000 too. I did have HCT on there too earlier as part of testing, and those were better than the LS, but I still didnt have SCSI with the A2091.

I need to test on the rev 4 again next to see if SCSI is working on there too.

Good result!!

Is it possible to do up a dummys guide for us home-novice people?

Just thinking out loud... what about a video? Can that be done?

Yes, I will do a video at some point soon perhaps! Will test the rev 4 tomorrow with ALS chips too. One of the problems with 2000's is there are variations between the boards, and lots of recommended mods etc. My cased rev 6 A2000 needs testing with this too - I cannot remember if that has ALS chips there already or not, but I do know all the other mods / fixes have been applied to my cased A2000.

Watching with interest - I have a boggo unmodified rev 6.2 A2000 and an A2091 with 5.92 ROMs and it doesn't boot at all with the TF536 installed.