NetBSD/sparc64 9.0 hanging up on Sun Ultra 5

[lorecast162 <lorecastcauli%gmail.com@localhost>]

Hi. I wanted to try running something different and more modern on my
old Sun workstation/server here.
So I tried running NetBSD on it since it's the only BSD I know can run
a X11 session on it.
I burned an ISO, checksum turned out good and I can boot it with boot
cdrom on my machine
The console goes forth for a while but then it goes black screen and I
can do nothing with Stop-a, the status lights dont react to me
pressing caps-lock etc, nothing shows up on the console.
I realized it does this right after the line saying `[1.0000000]
machfb0 4096 KB SGRAM 98.924 MHz, maximum RAMDAC clock 230MHz
post_div: 2 log2_post_div: 1 mclk_div: 228`.
I've put a video on yt with the machine booting here:
https://youtu.be/vVXH6TgBaFg (it's not on a CRT monitor so don't worry
about flicker)