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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
1.8. Environment Variables 1. Abstract 1.10. Command Interpreters
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