Template:RockchipBootPriority

The Boot order between eMMC and SD card

By default, the system will be booted from the TF card first, but this is not the case under all conditions. This section will explain all situations in detail;

Quoting the description of Rockchip official document [1], the system boot program (Loader) is divided into the following 2 types:
1) U-Boot TPL/SPL (i.e. upsream U-Boot, also called mainline U-Boot)
2) Rockchip MiniLoader

Things to note:
1) All ROMs released by FriendlyELEC adopt the second type, namely Rockchip MiniLoader
2) The third-party firmware usually uses the first type, namely U-Boot TPL/SPL

The following situations will always start from eMMC:
If the system in the eMMC, or the system in the TF card uses the first Loader type U-Boot TPL/SPL, it will always boot from the eMMC;
If you want to boot from the TF card, there are the following methods:
Method 1: Clear the Loader on the eMMC, the clearing method is as follows, after starting from the eMMC, enter the following command on the command line to clear the Loader on the eMMC:

dd if=/dev/zero of=/dev/mmcblk0 bs=8M count=1

Method 2: Insert the TF card, short-circuit the Maskrom contacts and then power on (need to keep the short-circuit for about 3 seconds), it will start from the TF card

The summary is as follows:

eMMC current system	TF card current system	Boot priority
No system	Any image	TF card
FriendlyELEC's image	FriendlyELEC's image	TF card
FriendlyELEC's image	Image with Mainline U-boot	eMMC
Image with Mainline U-boot	FriendlyELEC's image	eMMC
Image with Mainline U-boot	Image with Mainline U-boot	eMMC