I ordered an Orange Pi 4 a couple weeks ago, and it showed up on Wednesday. Last night I started tinkering around with to see if I could get Armbian up and running on it. First thing I did was to hook up my USB-to-TTL debugger to it (no SD card inserted). But when I powered it on, all I'm getting over the serial connection is garbage. With my other OPi's, I'm used to getting U-Boot messages -- but this was far from that:
The garbage settles dow
Which baud rate did you choose ?
All RockChip SoC are defaulting to 1500000 baud ...
EDIT : Sorry, I didn't look at your screenshot right ...
So, maybe the eMMC has Android installed by default and choose a different baud rate.
This Android U-Boot maybe doesn't provide option to stop and boot from eMMC.
EDIT2: To boot from SDCard, you will have to find TP50265 and TP50272 test points and short them together, that will disable the eMMC.