RedBoot
Table of Contents
Bootloader Initialization
RedBoot will emit a number of important details upon execution. The following example is from the i.MX31 ADS board. Your mileage may vary depending on the version of RedBoot and the board that is used.
With RedBoot in flash, the board outputs the following on the serial port at power-on/reset:
++... Read from 0x07ee0000-0x07f00000 at 0xa1fe0000: . ... Read from 0x07ed3000-0x07ed4000 at 0xa1fff000: . Booting from [NOR flash] ... waiting for BOOTP information ... waiting for BOOTP information Ethernet eth0: MAC address 00:04:9f:00:2e:af IP: 192.168.2.79/255.255.255.0, Gateway: 192.168.2.2 Default server: 192.168.2.20 RedBootTM bootstrap and debug environment [ROMRAM] Non-certified release, version FSL 200610 - built 10:26:48, Mar 9 2006 Platform: MX31 ADS (Freescale i.MX31 based) PASS 1.1 [x32 DDR] Copyright (C) 2000, 2001, 2002, 2003, 2004 Red Hat, Inc. RAM: 0x00000000-0x07f00000, [0x00013e40-0x07ed1000] available FLASH: 0xa0000000 - 0xa2000000, 256 blocks of 0x00020000 bytes each. RedBoot>
Configuring the Network Interface
Finding and Changing the MAC Address
The MAC address in normally displayed when the board is reset. If the MAC address is not set you can use the setmac command to do so:
RedBoot> setmac MAC address: 0x00:0x04:0x9f:0x00:0x2e:0xaf
Changing the IP Address
The IP Addresses of the board and tftp server are set using fconfig. The fconfig command prompts you for values for a series of configuration options.
RedBoot> fconfig Run script at boot: false Use BOOTP for network configuration: true Default server IP address: 192.168.2.20 Board specifics: 0 Console baud rate: 115200 Set eth0 network hardware address [MAC]: false GDB connection port: 9000 Force console for special debug messages: false Network debug at boot time: false
The IP address will be set with these values after a reset. It can also be set using the ip_addr command, which takes the following format:
ip_addr [-b ]
[-l local_IP_address[ netmask_length ] ]
[-h server_IP_address ]
[-d DNS_server_IP_address ]
| Flag | Description | Default |
| -b | Use DHCP to determine address. | Off |
| -l local_IP_address[ netmask_length ] | The IP address that RedBoot should use, and optionally the netmask length. | None |
| -h server_IP_address | The IP address of the default TFTP server. | None |
| -d DNS_server_IP_address | The IP address of the DNS server to resolve host names. | None |
IMPORTANT! The -b flag is not available in every version of RedBoot.
Example:
The following command loads an IP address using DHCP:
RedBoot> ip_addr -b
Downloading the Kernel
Once the network interface is configured, the kernel can be loaded via TFTP using the load command. It takes the following format:
load [-v ] [-d ] [-r ]
[-h server_IP_address ]
[-f flash_location ]
[-b ram_location ]
[file_name ]
| Flag | Description | Default |
| -v | Display a spinner to indicate progress | Off |
| -d | Decompress gzipped file | Off |
| -r | Raw or binary data. Must use -b or -f | Off |
| -h server_IP_address | TFTP Server IP Address | Value set by ip_addr or in config |
| -f flash_location | Location in flash memory to load file. | Set by data format |
| -b ram_location | Location in RAM memory to load file. | Set by data format |
| filename | Name of file to download from the server. | None |
Example:
The following command loads the raw file zImage from the server determined by ip_addr to the RAM location 0x01008000. It will also display a spinner.
RedBoot> load -v -r -b 0x01008000 zImage
Booting the Kernel
The loaded kernel is booted using the exec command. It takes the following format:
exec [-w timeout ]
[-r ramdisk_address ]
[-s ramdisk_length ]
[-b load_address {-l load_length} ]
[-c kernel_command_line ]
[entry_point ]
| Flag | Description | Default |
| -w timeout | Time to wait before execution | 0 |
| -r ramdisk_address | Address of the initrd image | None |
| -s ramdisk_length | Length of the initrd image | None |
| -b load_address | Address of the kernel image | Set by load |
| -l load_length | Length of kernel image | None |
| -c kernel_command_line | Command line passed to Linux kernel | Determined by kernel configuration |
| -x | Boot kernel with endianess opposite that of RedBoot | Off |
| entry_point | Starting point of execution | Implied by architecture |
Example:
The following example will execute a kernel loaded via the load instruction with the given command line.
RedBoot> exec -c "noinitrd console=ttymxc0,115200 \
root=/dev/nfs nfsroot=192.168.2.19:/opt/timesys/linux/6.1/armv5l-std/rfs \
init=/linuxrc ip=192.168.2.12:192.168.2.13"
Booting from Flash
The following section describes how to kernel from flash.
Determine Flash Size
The flash size is displayed by Redboot when the board is reset.
Example:
FLASH: 0xf0000000 - 0xf2000000, 256 blocks of 0x00020000 bytes each.
Initialize the Flash
You must execute the fis init command to initialize the FIS on the board.
This command should only be executed once, when the board is booted for the first time.
fis init [-f ]
| Flag | Description | Default |
| -f | All blocks of flash memory (except for the boot blocks) will be erased | Off |
Example:
The following example formats the flash memory.
RedBoot> fis init -f About to initialize [format] FLASH image system - continue (y/n)? y *** Initialize FLASH Image System ... Erase from 0xf0040000-0xf1fc0000: ......................................... ............................................................................... ............................................................................... ............................................... ... Erase from 0xf1fe0000-0xf1fe0000: ... Erase from 0xf2000000-0xf2000000: ... Unlock from 0xf1fe0000-0xf2000000: . ... Erase from 0xf1fe0000-0xf2000000: . ... Program from 0x0ffdf000-0x0ffff000 at 0xf1fe0000: . ... Lock from 0xf1fe0000-0xf2000000: .
Listing Flash Partitions
After flash is initialized the following default flash partition map (FIS directory) may be listed using the fis list command.
fis list
If the kernel is built with CONFIG_MTD_REDBOOT_PARTS enabled, you cannot define any partitions statically. Instead, you should use FIS to create and initialize partitions.
Example:
The following example lists the default RedBoot partitions:
RedBoot> fis list
Name FLASH addr Mem addr Length Entry point
RedBoot 0xF0000000 0xF0000000 0x00040000 0x00000000
RedBoot config 0xF1FC0000 0xF1FC0000 0x00001000 0x00000000
FIS directory 0xF1FE0000 0xF1FE0000 0x00020000 0x00000000
Writing the Kernel to Flash
To store the kernel in flash:
- Use load to download the kernel image from the TFTP server.
- Use fis create to create a FIS directory and copy the image to flash.
- Use fis list to verify the contents of your flash.
fis create -b mem_base
-l length
[ -r ram_addr ]
[ -f flash_addr ]
name
| Flag | Description | Default |
| -b mem_base | Address of data to be written to the flash. | None |
| -l length | Length of data area to copy | None |
| -r ram_addr | Address where the image should be relocated to by the fis load command. | None |
| -f flash_addr | Address in flash to occupy. | First free Vblock |
| name | Name of flash partition | None |
Example:
- Load kernel 'zImage.iq81342' to memory address 0x01008000:
RedBoot> load -r -b 0x01008000 zImage.iq81342 Using default protocol (TFTP) Raw file loaded 0x01008000-0x01152c43, assumed entry at 0x01008000
- Create an fis directory at 0xf0040000 called Kernel:
RedBoot> fis create -b 0x01008000 -l 0x01152c43 -r 0x01008000 -f 0xf0040000 Kernel ... Erase from 0xf0040000-0xf11a0000: ........................................... ................................................................................. ............... ... Program from 0x01008000-0x0215ac43 at 0xf0040000: ........................... ................................................................................. ............................... ... Unlock from 0xf1fe0000-0xf2000000: . ... Erase from 0xf1fe0000-0xf2000000: . ... Program from 0x0ffdf000-0x0ffff000 at 0xf1fe0000: . ... Lock from 0xf1fe0000-0xf2000000: .
- Verify the contents of your flash:
RedBoot> fis list Name FLASH addr Mem addr Length Entry point RedBoot 0xF0000000 0xF0000000 0x00040000 0x00000000 RedBoot config 0xF1FC0000 0xF1FC0000 0x00001000 0x00000000 FIS directory 0xF1FE0000 0xF1FE0000 0x00020000 0x00000000 Kernel 0xF0040000 0x01008000 0x01160000 0x01008000 RedBoot>
Loading the Kernel from Flash
The kernel can then be loaded into memory and booted using the fis load command.
fis load [-b memory_load_address ]
[-c]
[-d]
name
| Flag | Description | Default |
| -b memory_load_address | Address in RAM to load file. | Defined in partition table |
| -d | Decompress gzipped image | Off |
| -c | Print checksum of image | Off |
| name | Name of flash partition to load | None |
Example:
The following example loads an image from the "Kernel" partition and boots it.
RedBoot> fis load kernel RedBoot> go -n Uncompressing Linux.............................................................. ........................... done, booting the kernel. Linux version 2.6.11-timesys.1 (root@bslave04) (gcc version 3.4.1 20040714 (TimeS ys 3.4.1-7)) #1 Fri Dec 2 10:48:46 EST 2005 ... etc..
MTD Boot Partitions in Linux
If CONFIG_MTD_REDBOOT_PARTITIONS is set in the kernel configuration, then the FIS directories will appear in the kernel boot log as follows:
Searching for RedBoot partition table in phys_mapped_flash at offset 0x1fe0000
6 RedBoot partitions found on MTD device phys_mapped_flash
Creating 6 MTD partitions on "phys_mapped_flash":
0x00000000-0x00040000 : "RedBoot"
0x00040000-0x011a0000 : "Kernel"
0x00040000-0x011a0000 : "Kerne"
0x011a0000-0x01fc0000 : "unallocated"
0x01fc0000-0x01fc1000 : "RedBoot config"
0x01fe0000-0x02000000 : "FIS directory"
