Amiga explorer won't write ndos ADF's

[Jonno]

Hi all.

First time poster here.

I've searched through loads of threads but nothing seems to be exactly the problem I am having.

So, I can transfer ADF's successfully from PC to Amiga via serial only if those ADF's are ones that boot via workbench.

However, any adf that doesn't (say for example magic pockets) I constantly get a checksum error when the disk is finished. Ive tried cancelling the error. I've tried ignoring it and doing the three finger salute reboot, but all that does is resets and then the error still comes up.

It's frustrating that I can do some but not other adfs.

Any assistance would be greatly appreciated.

Sorry for such a long initial post, but it's been driving me nuts.

I have an a500, with wb 1.3. 1mb memory.

Thanks all.

Jonno..

[desiv]

It's been a long time since I used Amiga Explorer, but I usually used Transwarp on the Amiga side and ADF Sender Terminal to write most of my ADFs before I got my Kryoflux.

http://adfsender.stoeggl.com/

[thomas]

Originally Posted by Jonno

However, any adf that doesn't (say for example magic pockets) I constantly get a checksum error when the disk is finished. Ive tried cancelling the error. I've tried ignoring it and doing the three finger salute reboot, but all that does is resets and then the error still comes up.

Well, I doubt this is AE's fault.

If the error persists after a reboot (with the offending disk in the boot drive), then you've probably got a boot block virus which overwrites the boot block of each new disk with something which acts like a DOS boot block.

You have to get rid of this virus, otherwise you will infect all your floppy disks.

Switch off the computer and then boot from a known good floppy disk. Then kill the boot block of each other disk.

If a the boot block of an NDOS disk has been overwritten, the whole disk is useless and can be formatted or reused for another ADF file.

[MageMaster]

Guess I need add that to my learn list being so new to real hardware and never really messing with floppies and didn't realize Amiga had virus issues.

[Jonno]

Hi Thomas. How do I kill the boot block of the Disks?

Last time I encountered a virus on floppy disk was about 25 years ago ??

[Jonno]

Well. This has me beat currently.

I can write normal dos disks no problem whatsoever. Even using the parallel way of transferring from pc to amiga (which works well). but doing none dos disks is just not working. I have even downloaded an Amiga format adf with anti virus on it and it picks nothing up. I am at a loss now.

Any help would be really appreciated.

Jonno.

[desiv]

Have you tried formatting the blank floppy in the Amiga before writing an image to it? Just a standard format. I seem to remember I had to do that sometimes?
Also, have you tried the ADF on WinUAE to make sure it works? Just checking.
Also, just in case, for testing use 9600 baud. It's generally pretty safe. (I don't think you are having a baud issue, but I always dropped my speed when I was having issues..)

[Jonno]

Hi Desiv.

Yep. Done the formatting thing. Formatted with workbench and also done with xcopy. Adfs work in winuae. Can I check this virtually? In other words. Can I run Amiga explorer inside winuae and transfer from outside winuae on the same PC?

Does that make sense? This might at least help me eliminate any hardware issues. Having said that. I have 3 A500s and they are all doing the same thing.

[desiv]

I'm at a loss then. You might try ADFSender Terminal and transwarp (mentioned above) just to see if it is an AmigaExplorer glitch...
I did most of my transfers with that combination.
Maybe there is something wrong/corrupt with your AmigaExplorer executable? (I don't think so, but..)

[Jonno]

Tried transwarp as well. It will do everything else just not the ndos Disks. It is driving me batty ??

[thomas]

Originally Posted by Jonno

I can write normal dos disks no problem whatsoever.

I wouldn't be so sure. As I said above, the virus acts like a DOS bootblock. So on normal DOS disks you won't recognise the infection. You should consider all floppy disks which you inserted into the drive without write protection in the past are now infected.

Using another program to transfer ADFs does not help. Whenever a program writes to a disk, the virus writes itself into the boot block.

The first thing to do is to find a boot disk which is not infected. This is the most difficult part.

Switch off the Amiga. Enable and never again remove the write protection from the clean disk. Insert the clean disk and start the computer. Only now the Amiga itself is no longer infected. Whenever you boot from an infected disk, you have to start all over again.

Now insert each infected disk and enter install df0: to write a proper boot block to it or format drive df0: name empty to overwrite the entire disk.

You might want to use one of the anti-virus programs from this site: https://www.vht-dk.dk/amiga/download.htm

[Jonno]

So. I think i may have discovered what is going on..

There was a previous post i came across (from 2003) that stated that the bootsector was being changed on the transferred adf.

So i grabbed a hex comparison program and it turns out the original and the transferred are different. Considerably different.

They are different all the way down to OFFSET 00000400, then it looks like they match.

[thomas]

What I said: the original boot code (right) has been replaced by malware code (left).

The first two sectors (two times 512 bytes = 2 * 0x200 = 0x400) of the floppy disk contain the boot code.

Each floppy disk you insert into the drive without write protection will get this malware code written to it. For DOS disks you won't recognise because the malware code does the same as the normal boot code (plus starting the virus) but for NDOS disks, it destroys the boot loader as if you installed a DOS boot block to the NDOS disk.

As long as your Amiga is infected, you have no chance to produce a clean disk. You have to find a disk which is already clean. Or try if one of the anti-virus programs recognises the virus and can kill it from memory.

[Jonno]

Just confirming Thomas. you mean the other way round? :-)

The original boot code is on the left.

[AMIGASYSTEM]

Ciao Jonno, I am attaching an ADF that contains "ProoBoot" that will allow you to clean up the infection, you can transfer this "Bootblock" to any other floppy with which you will have protection on every floppy.

"ProoBoot" has a Purple screen, if an infection is present the screen will be vibrated, in the ProoBoot menu you will also find other utilities.

[Jonno]

Cool AMIGASYSTEM, I will try this out and let you know how i go.

[Jonno]

Ok, next dumb question.

How do i transfer the bootblock?

Sorry for all the questions :-(

Jonno.

[AMIGASYSTEM]

Simple, started "ProoBoot", eject ADF, insert ADF where do you want to copy BootBlock and press F4 key

[Jonno]

AMIGASYSTEM and Thomas.

I owe you both a great big thank you!!

It was a virus!!!

So. Amigasystem. Your file copied fine, but the virus overwrote your boot disk as well. I then checked it in Winuae to see what it was supposed to do.

Then i remembered a disk in amongst all the ones i got with the machine that had a similar boot screen. I used the one i had and BINGO! It found a virus.

So i cleaned all the disks i needed to use to get the ADF transfer working, crossed my fingers and YAY! it worked.

If i could send you a virtual beer then i would.

You have saved me from going insane :-)

Thank you both again!

Jonno.

[AMIGASYSTEM]

Originally Posted by Jonno

A

So. Amigasystem. Your file copied fine, but the virus overwrote your boot disk as well. I then checked it in Winuae to see what it was supposed to do.

Strange, in any case you could protect from writing ADF "ProoBoot"


I'm glad you solved it and I think this discussion can also interest others who have the same problem.