OpenWrt no longer fits in 4MB of flash, so current OpenWrt wouldn't even fit in a 2MB SPI.
I would love to at least have some form of bootload (chooser) available in the 2MB SPI, sometime similar to rEFIf or rEFInd to choose another boot device option. It would be nice if it also had the ability to download and flash base OS images directly from orangepi's site.