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I need FAT16 partition for Computer recovery process - (be able to access it form DOS) and I have only 2 pieces of 4GB flash.

I can't format 4GB to FAT16 with 512 B allocation unit (and with more it won't be supported by DOS)

Windows doesn't let me to delete and recreate smaller partitions.

What's the best way to achieve it. (I'm quite concerned about stability as I don't want my BIOS recovery rutine crash in the middle because of FAT coruption)

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You may use EASEUS Partition Master Home Edition to partition the key.

EASEUS should be able to format in FAT16.
If it cannot, see How do I format at USB Flash Device to be FAT16?, where the tool to is:

FORMAT drive: /FS:FAT16

(don't use the wrong drive-letter!)

Just be aware that for a partition greater than 512MB, you will only be able to store 512MB in any one folder.

You don't need to worry about the BIOS, since booting is from the hard disk, not from USB. In any case, partitioning the USB will destroy all data on it, and the BIOS does not live on the USB.

If Windows cannot detect the USB, see the advice in Windows Can’t See USB Hard Drive.
If that doesn't help, see A computer that is running Windows XP cannot detect a USB flash drive.

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new BIOS is on the USB so any read error while patching up may screw totaly. – Hurda Oct 3 '10 at 11:09
EASEUS Partition Master Home Edition doesn't "see" USB flashdisk – Hurda Oct 3 '10 at 11:18
I added some more stuff. I don't understand how the BIOS can be on the USB. – harrymc Oct 3 '10 at 11:25
If you flash BIOS you usualy do it from USB drive, more usualy you do it when you try to recover damaged BIOS. – Hurda Oct 3 '10 at 13:20
I'm totally confused now: Does the computer boot or not? Is the BIOS damaged? What's going on? Could you please re-formulate the question so we can understand what exactly is the situation and what is the problem. – harrymc Oct 3 '10 at 14:00

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