There’s already a method to boot Android from an SD Card on RK3188 devices, which should work with all Rockchip RK3188 devices. Ian Morrison (Linuxium) has now provided a instructions to boot Linux or Android from a (micro) SD Card in Rockchip RK3288 based devices, leveraging work from linux-rockchip community, and especially naobsd.
The Android flashing method is slightly different between RK3188 and RK3288, because most Rockchip RK3288 devices make use of eMMC flash, while older Rockchip RK3188 products feature NAND flash, and it appears Rockchip RK3xxx boot priorities (in the BootROM stored in the SoC itself) are as follows: eMMC, SD card, and NAND flash. All that means is that an updated version of the bootloader is needed which looks for a bootable SD card, and although very unlikely, your device could end up being bricked during this procedure...
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