I knew this was coming
I have not touched this for a couple of months so let me try to remember the details...
I got the sources for u-boot and the kernel from LeMaker GIT here:
https://github.com/LeMaker/lemaker-bsp. LeMaker makes a board, the BananaPi, of which the OrangePi is a clone. So using the source for the BananaPi is the easiest starting point.
I replaced the FEX file of the BananaPi by a FEX file that I got from a tech guy on the OrangePi forum and that I tweaked further to recognize all the features of the OrangePi. I modified some header file from the lemaker u-boot to allow the board to boot from a ext4 partition (instead of ext2 by default).
I compiled u-boot and kernel and generated the HW pack.
I installed arch on an SD card. I followed the instruction from another ARMv7 Allwinner A20 board (pcDuino 3) found here:
http://archlinuxarm.org/platforms/armv7 ... r/pcduino3At step 6 of the instructions on the page above I used the u-boot-sunxi-with-spl.bin and boot.scr from the HW pack that I compiled myself.
I replaced the kernel from the arch root file system by the kernel from the HW pack that I compiled myself.
That's it. Boot and off you go. Good luck.
I don't know wheter it would work for the OrangePi Plus but as it is a different SoC (H3 and not A20) I would expect that a different kernel is required.