Yeah, that photo I posted is slightly wrong.When I installed a uart header in one of my sabrinas last year, I used this image from the unlock writeup as reference for the serial connections:
View attachment 5703681
and installed the uart header thusly:
View attachment 5703683
Today I was booting ubuntu on sabrina and trying to interrupt uboot (fred has bootdelay set at non-zero value). I couldn't interrupt uboot.
It turns out that I had RX connected to the wrong location. It actually is here:
View attachment 5703691
The correct tx/rx locations also correspond to these locations on the edge connector:
View attachment 5703695
Please excuse this post if this info has been mentioned previously.
Sorry about that! Happy you got it fixed.