I have only recently been able to get my LaFrite 512, no EMMC to boot armbian.
My errors were legion. Might I suggest:
1. write the spi update image with the dd command, I had used etcher to no avail
2. make sure you use the USB port nearer the gpio pins
3. connect the hdmi output on the board to a monitor or use the serial header pins so that you'll have visual confirmations of what is going on
4. if the spi update image is newer than the board's image the update should be applied. My board was out of date and the image was applied. I've no idea what happens if the board has the same or newer image. I wasn't patient or thorough enough to check.
5. Use etcher to write any of the currently posted minimal images to a usb drive of 8, 16, or 32 GB - don't use a larger usb drive. Do not use the Ubuntu server image - the apt sources are bad on that one.
6. put the usb drive with the linux image in the usb port further from the gpio pins -- the opposite of what is needed for the spi update. Again make user you can see what is going on when you boot - hdmi to monitor is fine. Plug a usb keyboard in the other usb port to make things easy.
7. Power on the board. I used an el-cheapo power supply and it worked just fine.
If you have a good usb drive the board should boot fairly quickly. There shouldn't be any or many failures on the way up. Again let me reiterate -- a small usb drive. Every 64GB and larger drive I tried failed during the boot process. You may have better luck, but start small to see it things work.
I had decided some months ago that my board was defective, it wasn't, my brain was (or is).
Hopefully some of my experiences will help.
BTW make sure you use the forky rolling release for your Radxa-2F, because unless Armbian has fixed the older releases, your wireless card's drivers will be deleted on an apt upgrade or an Armbian-upgrade.
Hope this helps.