8300 Elite won't boot from USB flash drive

[tcsenter]

Elite 8300 SFF PC.  I prepared a bootable USB flash drive but cannot get the Boot Menu or Boot Order configuration in BIOS to see the drive.  Exactly the same as in this other unresolved thread:  USB not available in Boot Menu

In "Device Configuration" (BIOS) it is listed, but NOT appear in the Boot Order configuration, even if I save changes and reboot.  I have disabled UEFI and Secure Boot, enabled Legacy BIOS, as I intend to install Windows 7 x64.  During boot I press ESC or F9 to show the boot menu and the USB drive is not listed.  All USB ports are enabled.  Tried front and back ports (except the USB 3.0 ones since W7 does not have in-box driver support for USB 3.0).  I tried preparing it with both Microsoft USB DVD Tool and Rufus.

The flash drive has worked fine with several other PCs.  e.g. I have HP Pro 4300 SFF and the flash drive boots no problem there it is configurable in BIOS and selectable in Boot Menu.

First attempts on Elite 8300 was with BIOS v2.99.  But I also tried it after updating the BIOS to v3.03 because the release notes remarked about improving USB support, but there was no change same problem.

[soccer_dan]

this has always worked for me

Diskpart

> list disk

> sel disk # (the usb disk number listed)

> clean

> create partition primary

> sel part 1

> format fs=fat32 quick

> active (makes it bootable)

> assign (give it a drive letter)

> exit

then, open your Windows 7 iso file and copy drag/drop the contents to the usb key

See if that works

[NAVM · Accepted solution]

Take the CMOS battery out press CMOS Reset switch on the systemboard put the CMOS battery back, Restart the unit set date and time in the BIOS and check if that helps. 

[tcsenter]

Thanks, that did it.  I had previously loaded Setup Defaults in BIOS before and after the BIOS update, saved and exited then tried again, but nothing changed.  Loading Setup Defaults usually accomplishes the same thing but apparently not on this BIOS.

It also caused a complete rebalance of PCI resources the USB 3.0 controller is being detected again as a 'new' device even though it was already installed with the correct drivers.  Anyway it's all working now so thanks for that.

[Computer_Dude]

Thanks for the tip, worked for me.