December 24, 2021

Orange Pi 4 (Rockchip 3399) Android

The first thing I decided to do, was to fire up my unit with eMMC and find out just what was in eMMC (it is Android as it turns out).

Although the spec indicates 5 volts and 3 amps, I used a 2 amp supply without any problems.

The serial port runs at 1500000 baud, which is a crazy high baud rate. My CP2102 usb to serial gadget did not support this speed, but I have a bunch of CP2104 usb to serial gagets, and they worked fine. I connect 3 wires, ground, RxD and TxD.

The 3 pin serial console header on the board has signals in this order: Ground, Rx, Tx - with ground closest to the corner of the board. I connect Tx on my serial dongle to Rx on the board, and Rx on my serial dongle to Tx on the board.

It boots up and offers you a shell without logging in. You are running as user "shell", but simply typing "su" makes you root.

Interesting tidbits from the serial messages

U-Boot 2014.10-RK3399-06 (Nov 27 2019 - 15:05:49) #Boot ver: 2019-11-27#1.15 Linux version 4.4.126 (orangepi@ubuntu) (gcc version 6.3.1 20170404 (Linaro GCC 6.3-2017.05) ) #67 SMP PREEMPT Mon Oct 28 09:55:27 CST 2019

Getting to the U-boot prompt

So far I have not managed this, so either this is disabled or there is a tiny time window to do so.

Overwrite Android

I spent an hour or so fiddling with the Android image, then figured out how to ditch it and replace it with Debian. Notes on how to do this elsewhere. It is quick and easy once you have Debian on an eMMC card.

Have any comments? Questions? Drop me a line!

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