As @grimler stated in MR !5887 (comment) [1], samsung-jackpotlte,
samsung-xcover4lte, and samsung-a30 share the same name for Wi-Fi
proprietary blobs, and packaged in their own specific firmware package.

The problem is these firmware packages put files in the same directory
as `firmware-samsung-a51`: /lib/firmware/postmarketos/mx140/. This opens
up the probability of conflicting blobs when multiple firmware packages
are installed on the system, resulting in wrong blobs used.

To ensure that this firmware is located in its own directory, move
`samsung-a51` blobs into its own subdirectory. This way, `a51` blobs
will stay intact whether multiple firmware packages are installed.

[1] !5887 (comment 459185)

Successfully built and booted postmarketOS on Samsung Galaxy A51. It's based on Exynos 9611 SoC.

Currently, these are tested working:

- Boots from internal storage
- Display (DECON driver needs to be patched. Included in the kernel package)
- Framebuffer (additionally with msm-fb-refresher to refresh the screen)
- Touchscreen
- USB Networking (RNDIS)
- Wi-Fi

Tested UI environments: XFCE 4 & Console.

Wiki: https://wiki.postmarketos.org/wiki/Samsung_Galaxy_A51_(samsung-a51)