Installing Freebsd on RPI 4

Hello all!

I'm new to the arm world. I've bought a Raspberry PI 4 that came
with it's raspbian OS working as expected. As it comes with systemd,
I flashed a Devuan Image on an empty Micro SD card via "dd" from my
freebsd PC and now it runs happily. From dmesg on Devuan I see:

[    0.000000] Machine model: Raspberry Pi 4 Model B Rev 1.4

(I can post the whole dmesg output, if relevant, tough it is a bit long)

Being Rev 1.4 > 1.2, I did replace u-boot.bin following wiki instructions
found at https://wiki.freebsd.org/arm/Raspberry%20Pi and flashed the
13.0-RELEASE with dd on a clean Micro SD card.

Now, if I try to boot from it I only get a colored patch on the screen
attached to the RPI 4 through the same HDMI cable that works well with
reaspbian and Devuan.

What did I do wrong?

Thanks to all in advance,

Luciano.
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