A-P

Along with "overlays=spi-jedec-nor", do you have "param_spinor_spi_bus=0" ?
Did you inspect "dmesg" to see any related errors ?
 

@A-P There is no more detail in dmesg about the error?
 
It's very strange that @glow solution to busnum=0 works as OPIZERO has no pins to connect to SPI0 bus in the GPIO header. Check this:
 

 
Busnum=1 will use the pins for SPI1: SPI1_CLK,SPI1_MISO,SPI_MOSI and SPI1_CS.
 
For other needed pins (this will depend on the screen) you need to select the GPIOS manually. Be aware of the mapping:

Check your wiring to verify it is correct with fbtft parameters. What errors are shown in dmesg?
 
For checking that thet SPI1 works well you can use the spi-dev overlay simply puting this in /boot/armbianEnv.txt:
overlays= <other overlays> spi-spidev  
param_spidev_spi_bus=1
after reboot /dev/spi*  files should be present.
 

You are not hijacking the thread at all! Your experience is very close to mine, and I started this thread.
 
In your case, have you tried to use busnum=0?  Modprobe completes without errors for me with busnum 0 works, but not busnum 1.

This is the legacy kernel. You need to enable spidev in script.bin (if it's not enabled already) and use flashrom (from flashrom package) on /dev/spidev0.0 to write the u-boot

Booting from SPI-NOR doesn't need other things than the u-boot-sunxi-with-spl.bin in the flash, which a bit less than 500K.
The kernel itself along uinitrd and dtb should be located elsewhere.
I've never try to boot in NFS or TFTP yet, but booting from USB drive just works fine.
(BTW, pushing u-boot-sunxi-with-spl.bin into flash isn't done by nand-sata-install, nand-sata-install is used to copy sdcard into other storage such USB drive or eMMC)

For flashing the SPI-NOR, you need to get "mtd-utils", either from apt-get or from sources.
You need to add in the /boot/armbianEnv.txt the following overlay :
overlays=spi-jedec-nor Then, reboot, and check if SPI-NOR appears by doing "cat /proc/mtd". If you have mtd partitions, then install u-boot-spl using this command (check previous partitions to make sure u-boot is mtd0) :
flashcp /usr/lib/linux-u-boot-dev-orangepipc_5.27_armhf/u-boot-sunxi-with-spl.bin /dev/mtd0 Next steps are for copying your sdcard into you already inserted usb drive by using nand-sata-install. After copy finished, edit the boot.cmd from your usb drive, this means probably /mnt/boot/boot.cmd if drive mounted in /mnt.
Change all "mmc" words by "usb" and add on top of boot.cmd the line "setenv devtype usb", save it and recompile it with "mkimage -C none -A arm -T script -d /boot/boot.cmd /boot/boot.scr".
Then, shutdown the board, remove the sdcard, and re-power the board. Check the boot log using USB-TTL adaptor. If everything fine, you should get into the login prompt. Bingo !