After transferring Armbian from SDCard to eMMC, next time you wish to boot SDCard, it will be less painful, no more needs of TP50265 ... Simply stop U-Boot with spacebar, then you can select SD with "setenv devnum 1" followed by "run mmc_boot".   You need to switch firmware to another version : mv /lib/firmware/brcm/brcmfmac4356-sdio.bin /lib/firmware/brcm/brcmfmac4356-sdio.bin-ORIG mv /lib/firmware/brcm/brcmfmac4356-sdio.txt /lib/firmware/brcm/brcmfmac4356-sdio.txt-ORIG cp