1.9. Boot Options

U-Boot supports many different ways to load and boot an image.

Basic command:

"bootm" - Boot Image in memory (RAM, flash)

Image:

Header + Payload

Header:

 

• Creation Timestamp
• Data Load Address
• Entry Point Address
• Data CRC Checksum
• Operating System
• CPU architecture
• Image Type
• Compression Type
• Image Name
  
  

Actions:

 

• test CPU architecture and OS
• test checksum (optional)
• if compressed, uncompress
• copy to load address
• prepare boot arguments
• start at entry point
  
  

Load image in memory:

 

• Serial Port: "loads" (S-Record), "loadb" (Kermit binary protocol)
• Ethernet: "tftp", "bootp", "dhcp", "nfs", ...
• Harddisk, CDROM: "ide read"
• CompactFlash card etc.: "ide read"
• USB Mass Storage Device: "usb read"
• SCSI Disk and CDROM: "scsi read"
• NAND flash with JFFS2 filesystem: "nboot"
• Disk on Chip: "doc read"
• PCI Bus: copy
• ...
  
  

Supported Filesystems (read-only):

 

• FAT
• Reiser
• JFFS2