Is it possible to extend a FAT16b partition and preserve the boot sector?

Question

I have a bootable USB thumbstick with FreeDOS. It's 512 MB FAT16B. The thumb drive itself is 4 GB, and I'd like to extend the bootable partition as much as possible (FAT16B supports at least 2 GB partitions, possibly 4 GB).

DISKPART> detail partition

Partition 1
Type  : 06
Hidden: No
Active: Yes
Offset in Bytes: 32256

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
* Volume 6     I   FD-SETUP     FAT    Removable    511 MB  Healthy

The catch is that diskpart refuses to extend this partition:

DISKPART> extend

Virtual Disk Service error:
The volume cannot be extended because the file system does not support it.

Is it doable? I don't mind losing the files as I can back them up and then restore, but I don't have any simple way of restoring the boot sector so I'd rather not lose it.

Answer 1

FAT16B is a pretty old format, dating from before Windows NT. So everything you do is going to be experimental in nature.

I would therefore counsel taking a backup image of the thumb drive in a format that can be restored. If possible, do the experiments on a virtual copy rather than on the real drive. I would suggest the VirtualBox disk formats of VDI or VMDK formats, for reasons listed below.

Here are some suggestions:

• Download VirtualBox images for older virtual machines exist for download in the webpage Virtual Disk Images. You could try an image up to and including Windows NT to resize the partition.

• Linux might still support this format when mounted as type MSDOS.

• Some third-party partition editor might know how to handle this format.

(I can only give theoretical advice since I have no personal experience with FAT16B.)