U-Boot uses a set of environmental variables to control the operation of the system. The flinfo command can provide an idea of the storage layout on the device, see below for an example: Devices using NOR flash typically use a portion of the NOR flash to store the bootloader and kernel. On systems that use raw NAND flash as the primary storage device, there is generally a secondary storage device used for low-level boot images such as U-Boot, the U-Boot environment, and the Linux kernel due to the complexities of bad-block handling with NAND flash. This is generally the same device that stores the U-Boot image and Linux Kernel. The U-Boot environment is stored in a pre-determined area of non-volatile storage. Available commands may differ between systems depending on applicable features. Individual command help can be accessed by passing the command name as an argument to the help command. To see all available commands, type help. U-Boot commands may be entered at this prompt.Macb0: link up, 100Mbps full-duplex (lpa: 0x45e1) This should bring up the U-Boot prompt as seen below:Īrea 0: C0000000 to C00041FF (RO) Bootstrap
DAS U BOOT TUTORIAL SERIAL
When initial boot messages are printed to the serial terminal, press Enter in the serial terminal application.After a serial connection has been established, reboot the board.Refer to the Serial Connections page or other documentation for more information. Configure a serial connection with the target board using the settings specified for the hardware.The following steps will interrupt the boot process and access the U-Boot prompt. By default, U-Boot is set up to automatically boot the OS after a set timeout.