If your OS upgrade image came with UpgradeUT.exe, I mean if you tried to upgrade your ipaq and got the popup screen “HP ROM UPGRADE Utlity v3.15” then the .nbf files couldn’t be inserted directly using host11.exe
Certainly, there is a situation you want to dump the rom image into iPaq in a straightforward manner, not guided by the fixed routine. in that case, you have to trim your file’s unnecessary portion.
Delete these inversed part and rename it to nk.nb0,
then set your ipaq to the usb memory upgrade mode and run host11.exe.
don’t forget to kill activesync when you do this.