Boot hangs with "dxe_update_mem_attrs ... addr is not page aligned" when a USB storage device is attached #835

Invalid call dxe_update_mem_attrs(addr:0x701A6680-0x701A767F, size:0x1000, +r, -wx)
 addr is not page aligned

The kernel never starts and a hard reset is needed.

It happens only when a Garmin USB device (watch or Varia radar, seen as a FAT volume GARMIN) is connected at boot, and not every time. Without such a device I have never seen it. My guess: the extra device shifts firmware memory allocations, and sometimes the kernel image ends up at an unaligned address.

rEFInd's log is identical for good and bad boots up to Launching 'vmlinuz-...', apart from the extra GARMIN volume, so the hang is inside shim.

Environment:

shim-x64-16.1-7 (Fedora 44)
rEFInd 0.14.2, signed with a MOK key, launched via shim
Kernel 7.2.11-200.fc44.x86_64
Secure Boot enabled
MSI B850M MORTAR WIFI, BIOS 1.A68 (09/07/2026)

Not yet tested with GRUB instead of rEFInd; I can do that if useful.

Should shim handle an unaligned address here, or is the caller passing a buffer it should not?

Attached: screen photo, rEFInd logs of a failed and a successful boot.