[Pi 5] Fatal firmware error on boot when non-FAT USB MSD inserted

[platinum95]

Describe the bug
This is a slightly odd setup but I believe it's still within the spec of the firmware as per docs, so this error seems like a bug.
The context here is that I'm trying to prioritise booting off a USB device, with fallback to SD card if no valid bootable USB is present. In other words, the 4 scenarios are:

• Valid FAT partition on USB stick -> Boot off USB.
• No USB stick -> Boot off SD card.
• USB stick with FAT partition on but no firmware files -> Boot off SD card
• USB stick with non-FAT partition -> Boot off SD card.

The first 3 scenarios are working as expected. The last one fails during bootloader. I've attached an image of the HDMI diagnostics output when a USB stick with a single NTFS partition is inserted in the Logs section below.

To reproduce
Set boot order to prioritise USB, fallback to SD.
Insert a NTFS-formatted USB drive, and a valid bootable SD card.
Attempt to boot.

Expected behaviour
Pi boots off the SD card.

Actual behaviour
'Fatal firmware error' occurs at addr 0x3fc1393c after the firmware attempts to read the USB partitions, and before it falls back to SD card.

System
Pi 5, bootloader 57db150d (2025/11/05)

EEPROM config:

[all]
BOOT_UART=1
POWER_OFF_ON_HALT=1
BOOT_ORDER=0xf614i
WAIT_FOR_POWER_BUTTON=1
USB_MSD_DISCOVER_TIMEOUT=1000

I know the MSD_DISCOVER_TIMEOUT is out of spec, but the error also occurs when it's at default value.

Logs

[pelwell]

Duplicate of raspberrypi/rpi-eeprom#776.

[lurch]

@platinum95 There's a fix being discussed / proposed over in that other issue if you'd like to have a look and help test it?