Then may want to make sure your device is using RK3288Loader_uboot_V2.17.02bootloader (or latter).
You can do so by loading the firmware file (currently installed in your device) in Android Tool, flashing the firmware with upgrade_tool, running ‘cat /proc/cmdline’ in a terminal, or simply trying a bootable SD card with the method below.
The Android flashing method is slightly different between RK3188 and RK3288, because most Rockchip RK3288 devices make use of e MMC flash, while older Rockchip RK3188 products feature NAND flash, and it appears Rockchip RK3xxx boot priorities (in the Boot ROM stored in the So C itself) are as follows: e MMC, 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.
If you want an image more suited to your hardware, you may have to use sd-create-linux script instead included in create-sdcard.7z previously downloaded together with relevant firmware files for Firefly-RK3288 board, Rikomagic MK802V, and Tronsmart Orion R28, and other hardware based on the same hardware platforms.
If you are pretty sure you need to upgrade your bootloader, download RK3288Loader_uboot_V2.17.02.bin, and flash it to your device in Linux with: first to make sure you are using the right storage device, or you may wipe out important data on your PC.
For extra safety, you may even consider doing this procedure from a virtual machine in Virtua Box.
That’s it now, you can just insert the SD card into your device to boot Android.
This is not a problem for Open Hour Chameleon since there’s no internal storage at all, so it will always boot from SD card and is really unbrickable.First, you’ll need to download create-sdcard.7z with the tools, and images required.