U-Boot¶

Introduction¶

RK U-Boot is developed based on the open source U-Boot and it has two work modes: bootstrap mode and download mode. The bootstrap mode is the regular mode of U-Boot. After the release of the embedded product, U-Boot always works under this mode, which is mainly used to load the kernel from the memory and open the operation system during the launching process. While download mode is mainly used to download the firmware to the flash memory. Long press the recovery button as soon as you power on and it can enter into the download mode. This page will give a brief introduction about the usage of U-Boot.

Compile¶

Build the U-Boot is similar to Build kernel. Before compiling, please write the default configuration into the .config file , execute it:

 cd SDK/u-boot
 make px3se_linux_defconfig

If you want to modify some options, you can also use:

 make menuconfig

Building u-boot:

 make

Generate image file after compiling:

 px3se_miniloader_v2.48.bin
 uboot.img

The combination of px3se_miniloader_v2.48.bin and uboot.img is a secondary bootloader, which supports eMMC and NAND flash memory at the same time.

Flash¶

Open the flash tool and connect the board with USB OTG cable. While connecting to power, hold the Recovery button to make the board enter into Loader mode. Select the compiled Loader file in the flash tool and click Execute to start flash, as shown in the following screenshot. _images/uboot_loader.png

Check whether you have flashed the new Loader correctly¶

If you have already flashed your newly compiled Loader successfully, you will find the following information in the debug serial port output while the device restarting.

Boot1 Release Time: Jan 22 2018 17:48:37, version: 2.47

If the Loader time and version printed out are same as the one you compiled(since the Loader of Firefly-PX3-SE is not open source, the Loader is upgraded by RK), it means that you have upgraded the Loader successfully.