Non-system disk or disk error is at least coming from the boot sector so that's a good sign that something is working (unless it is failing over to the hard drive and it's the VBR generating that message). Does the 386 definitely boot with other floppies? I have run into the floppy head not being able to seek for lack of lubrication, but the grinding sound during the BIOS disk seek made this obvious.

jakethompson1 wrote on 2026-07-13, 17:14:

Does the 386 definitely boot with other floppies?

Yes, I have an original version of MSDOS 4.01 and it boots on the 386. Also, I tried burning the .img file on different floppies, and I get the error nonetheless.

I assume not a 720k (which 4.01 would be) vs. 1.44mb issue, but I'd think even the boot sector wouldn't load to give you this error in that case.

I suppose sdc is a usb floppy.
I would make an image of an existing good floppy, then dd it back to a blank.

Also , depending what you want to do with this floppy, I like to have a tftp server, then you can boot from network with AllInOne, even with some ISA network cards.
Not exactly an answer to your specific problem here, but it helped me many times for a lot of things.

Are you absolutely certain that the image is good and for the same drive type that you are trying to boot it on.

I see that you are using LInux ... Is yours set up to be able to read a FAT floppy? ... if so, can you ls the content of the floppy? (ie: is the directory good)

Do you happen to have DosBox (or any other Virtual MAchine) installed? If so, can it boot the image? - DosBox> boot imagefile

On my MySite->Downloads you'll find DOSBOOT.ZIP which has known good boot images (I've booted them all in Virtual Machines - and written most of the more recent ones to physical disks and booted them on real hardware) for 13 different editions of DOS, including 6.22

DaveDDS wrote on 2026-07-13, 21:39:

Do you happen to have DosBox (or any other Virtual MAchine) installed? If so, can it boot the image? - DosBox> boot imagefile

He wrote he tried, and it boot.
I also tried the same Dos6.22.img on 86box and it works.

I'm unfamiliar with sudo, but maybe you need to supply an extra switch to write the boot sector. Try sodo /? and tell me what happens. That should give you some help information.

Hi, I've used to use WinImage on Windows for this purpose.
There's also a 16-Bit version for Windows 3.1x (WinImage 3).
On DOS, there's graphical (menu driven) image software such as Teledisk or Disc Copy Fast (DCF).
The latter supports the *.ima format, too. I've already tried out.

On Linux, there's a graphical image tool, "GNOME Disk Utility", though it's more like Win32 Disk Imager on Windows.
It's more useful for writing/reading images of HDD or SD card images than floppies, I suppose.

Btw, how about using rawrite instead of dd on Linux?
Back in the 90s, I remember, install floppies were often created using rawrite.
Edit: Hm, there's no Linux version. It runs on DOS, Windows..

Boot the 386 with the DOS 4.01 floppy and see if it will even read the DOS 6.22 floppy that you wrote. Before trying to troubleshoot a potential image writing issue (which I don't think it is tbh) you want to make sure the disk is readable across both drives.

Try installing mtools, you can use it on images as well as real floppies. You should be able to 'mdir' the dos622 IMG if it is a real FAT12 disk image.
Of course you should also be able to loop mount the disk image using losetup and mount, or just use the Gnome disk image mounter to check it's working/genuine.

dd is definitely what you should be using, normally for writing dos floppy images I don't use any block size or conv prams, and it just works.

Have you tried any other disks written by your usb floppy? I've a couple of different types of these drives and some are better than others.

NeoG_ wrote on Yesterday, 01:16:

Boot the 386 with the DOS 4.01 floppy and see if it will even read the DOS 6.22 floppy that you wrote. Before trying to troubleshoot a potential image writing issue (which I don't think it is tbh) you want to make sure the disk is readable across both drives.

This. Try just reading the image after booting with a known good boot disk.

nali wrote on 2026-07-13, 23:12:

He wrote he tried, and it boot.
I also tried the same Dos6.22.img on 86box and it works.

Ok, I've not used 86box, but I do boot floppy images all the time is DosBox, VMware and PcEm - the fact that the image boots tells me it's good.

Which means transfer of the image to a physical diskette isn't working. I don't use Linux much, I'm not intimately familiar with "dd"...
A good exercise might be to transfer the image to a disk, then read it back info another image and see if that matches the original image.
Then... binary compare of the two might help figure out how it is being modified.

popcalent wrote on 2026-07-13, 17:10:

sudo dd if=Dos6.22.img of=/dev/sdc bs=512 conv=fsync status=progress

I just asked a friend who uses Linux MUCH more than I do, a he said to try dropping "conv" he never uses it and thinks it might add metadata to the output somehow.

i still use windows tools for this no rocket science

zapbuzz wrote on Yesterday, 14:38:

i still use windows tools for this no rocket science

Exactly - this shouldn't be hard - I use my own XDISK(simpler for DOS/BIOS recognized format disks) or ImageDisk(more complex for ANY format disk) under DOS, DSKWRITE or WINIMAGE under Winblows.

But... OP was using "dd" within Linux.

popcalent wrote on 2026-07-13, 17:10:

$ sudo dd if=Dos6.22.img of=/dev/sdc bs=512 conv=fsync status=progress
1471488 bytes (1.5 MB, 1.4 MiB) copied, 162 s, 9.1 kB/s1474560 bytes (1.5 MB, 1.4 MiB) copied, 162.434 s, 9.1 kB/s

I just noticed this - common DOS disk images(.IMG) sizes are:

1160k    163,840 bytes 
2180k    184,320 bytes
3200k    204,800 bytes
4320k    327,680 bytes
5360k    368,640 bytes
6400k    409,600 bytes
7720k    737,280 bytes
81200k 1,228,800 bytes
91440k 1,474,560 bytes
102880k 2,949,120 bytes

So why exactly did "dd" transfer 1,471,488 bytes - not a full 1.44m disk image size.
There must be some sort of translation going on...

DaveDDS wrote on Yesterday, 18:03:

So why exactly did "dd" transfer 1,471,488 bytes - not a full 1.44m disk image size.
There must be some sort of translation going on...

It's a red herring, dd was set to output progress to the terminal so one of the in-flight progress lines was copied and pasted. The final byte count was as expected

12880+0 records in
22880+0 records out
31474560 bytes (1.5 MB, 1.4 MiB) copied, 177.923 s, 8.3 kB/s

I was curious and tried the same floppy image, from the same web site..
I used "sudo dd if=Dos6.22.img of=/dev/fd0 bs=512 conv=fsync"
On Debian Etch "status=progress" was not an option yet.
But I don't think it makes any difference.
Notice I use a real floppy drive, not a Usb.
It's a Supersocket 7 with a K6-2 550, nothing special.

It boot perfectly from the floppy.
That's why I suggested you check your Usb drive by coping a known working boot floppy.

1phil@scsi:~$ sudo dd if=Dos6.22.img of=/dev/fd0 bs=512 conv=fsync 
22880+0 records in
32880+0 records out
41474560 bytes (1.5 MB) copied, 105.787 seconds, 13.9 kB/s
5phil@scsi:~$ sync
6phil@scsi:~$ sudo mount /dev/fd0 /mnt/fd0
7phil@scsi:~$ ls /mnt/fd0
8attrib.exe    cd3.sys      deltree.exe   edit.ini    himem.sys  mouse.com   qbasic.exe    setver.exe    undelete.ini
9autoexec.bat  cd4.sys      doskey.com    emm386.exe  io.sys     mouse.ini   qbasic.hlp    share.exe     unformat.com
10c.bat         chkdsk.exe   drvspace.bin  fdisk.exe   label.exe  mouse.sys   restore.exe   sys.com       xcopy.exe
11cd1.sys       command.com  edit.exe      find.exe    mem.exe    mscdex.exe  scandisk.exe  tree.com
12cd2.sys       config.sys   edit.hlp      format.com  mouse.@@@  msdos.sys   scandisk.ini  undelete.exe

Since I'm perv, I also tried from BeOS 4.5.
I formated the floppy and dd the image again.
No special options, just dd.
It takes time on BeOS ...

1$ uname -a    
2BeOS k6 4.5 1000009 BePC
3$ dd if=Dos6.22.img of=/dev/disk/floppy/raw 
42880+0 records in
52880+0 records out
6$ sync

Guess what ?
It boot perfctly too.

The md5sum is:

1md5sum Dos6.22.img 
2a4a096cab6079c2cfa88a8bde0eac3aa  Dos6.22.img

I also downloaded the Dos6.22.img file from the given link, it is the correct size (1474560 bytes) and boots in DosBox, PCem, and from a real disk when written with either DSKWRITE or my own XDISK.

nali wrote on Yesterday, 22:59:

phil@scsi:~$ sudo dd if=Dos6.22.img of=/dev/fd0 bs=512 conv=fsync
1474560 bytes (1.5 MB) copied, 105.787 seconds, 13.9 kB/s

This shows the correct size for a 1.44m image!

popcalent wrote on 2026-07-13, 17:10:

$ sudo dd if=Dos6.22.img of=/dev/sdc bs=512 conv=fsync status=progress
1471488 bytes (1.5 MB, 1.4 MiB) copied, 162 s, 9.1 kB/s1474560 bytes (1.5 MB, 1.4 MiB) copied, 162.434 s, 9.1 kB/s

And the OP 's command does NOT!

So... if its the same image (@popcalent what is the exact actual size of your Dos6.22.img file?), why the different size - the only difference I see in the commands is "of=/dev/fd0" (which I assume is the 1st floppy) and "of=/dev/sdc" (which I assume is an SDcard?) also "status=progess" is missing in yours (Guessing that just control progress messages?)

Perhaps dd writing to an SDcard isn't the same as a floppy? - It certainly wouldn't be the same geometry.. but I would expect it to write the same number of bytes.

I know when I made a bootable CD(which is -way- different geometry) from a floppy image, the image stored on the CD is exactly the same as the original image of the floppy.