Input/Output Uart3 error(how to enable uart)

I’ll try to be short, im using an bananapi zero m2 hooked up to a normal genuino arduino uno from Uart3 rx to arduino tx port ( i havent found it but is uart3 pin 5v or 3.3v?). The OS thats etched on the banana pi zero is Arch linux. The ttyS0 and ttyACM0(through usb directly to arduino) work just fine (in 38400 clock 5v). But im assuming that the ttyS3 and others are deactivated. How would i go about to configure it? I hooked the gnd to pin 6 and arduinos tx to pin 10

The image uses uboot, which i havent managed to manually compile so i had to use an old image.

When i try to use the ttyS2-S5 they reply with a Input/Output error on the console

Oh btw i ended up solving it by just hammering the solution in u-boot aparently it comes deactivated by default and i have no idea on how you would go about activating it without either changing u-boots configs or changing kernel params before booting regardless this was kinda for prototyping and i dont need the full functionality of bpi zero so… might as well hammer the solution