Instant Flash doesn't find file on USB

Guys,

At Crucial's suggestion, I'm attempting to flash ASRock B550 Phantom Gaming 4 board from 1.4 to 1.7, to address flakiness in XMP2. When I first fired up the board, I was able to update flash from from 1.2 to 1.4 via Instant Flash.

My system (Ryzen 5 3600, 2x8 Crucial Ballistix DDR4-3200, WD SN 550 NVMe SSD, Radeon RX 560 4GB) is up and running fine, with the exception that XMP setting causes screen flickering and black outs. Crucial tech support suggested updating BIOS. If that doesn't address, they suggested the age-old process of running with 1 memory stick. What's interesting is I can go into UEFI and manually set the memory speed to 3200, and the system is stable.

Now my issue. I d/l'ed the 1.7 BIOS file, and put it on a thumb drive, formatted to exFAT (only option, besides NTFS). On two different thumb drives I get the message "no file detected on USB." I have Fast Boot disabled, and tried w/ Secure Boot both enabled and disabled. Same result, Instant Flash doesn't see the file on the thumb drive.

I'm sure I'm missing some setting in UEFI that's not letting the flash go forward. What might that be£ Looking forward to hearing what I'm missing, as a UEFI newbie.

TIA,

Jeff

RLGL, thanks for the reply. I received a post on another forum, confirming your take on the issue. I d/l'ed Rufus, to format to FAT32, as Win10 will only format to exFAT.

Just completed flash, now to see if XMP2 behaves better.

Jeff

RLGL, I have Win10 Pro, and the only formatting options I see are exFAT or NTFS, via either File Explorer or Disk Management.

If Win10 will format other formats than that, I'm wide open to being educated!

Jeff