linux-firmware >= 20250613.12fe085f-5 upgrade requires manual intervention

With 20250613.12fe085f-5, we split our firmware into several vendor-focused packages. linux-firmware is now an empty package depending on our default set of firmware.

Unfortunately, this coincided with upstream reorganizing the symlink layout of the NVIDIA firmware, resulting in a situation that Pacman cannot handle. When attempting to upgrade from 20250508.788aadc8-2 or earlier, you will see the following errors:

linux-firmware-nvidia: /usr/lib/firmware/nvidia/ad103 exists in filesystem
linux-firmware-nvidia: /usr/lib/firmware/nvidia/ad104 exists in filesystem
linux-firmware-nvidia: /usr/lib/firmware/nvidia/ad106 exists in filesystem
linux-firmware-nvidia: /usr/lib/firmware/nvidia/ad107 exists in filesystem

To progress with the system upgrade, first remove linux-firmware, then reinstall it as part of the upgrade:

# pacman -Rdd linux-firmware
# pacman -Syu linux-firmware