- Preparing the Target
- Preparing the Host
- Booting the Board
- Additional Information
This document will describe in detail the procedures for booting a Linux kernel image and mounting a root file system from an SD Card on the TI BeagleBone Black.
- Modern GNU/Linux Distribution. Timesys recommends one of the following distributions:
- Ubuntu (Most recent release or LTS)
- Fedora (Most recent release)
- Root or sudo permission on the Development Host.
- A copy of the Linux Kernel (uImage-4.1-ts-armv7l), device tree file (beaglebone_black.dtb) and Root File System (rootfs.tar.gz) for the Target Board downloaded from Factory. These are found in the output directory of your online build, or in the directory build_armv7l-timesys-linux-<libc>/images/ on the command line.
- An available USB port on your Development Host.
- A SD card slot or adapter on your Development Host.
To boot the TI BeagleBone Black, you will need the following items:
- TI BeagleBone Black
- Micro SD Card
- Micro USB Cable or 5V Power Supply
- USB TTL Serial Cable (Such as the FTDI TTL-232R-3V3)
Once you have all of the necessary components, you should perform the following steps:
- Connect the USB TTL serial cable to J1. The following connections are relevant:
Pin Function 1 GND 4 RX 5 TX
- Insert the SD card into your host machine. You will be loading your boot files onto this device.
- Connect the USB port of the board to the USB port of your workstation if powering the board using the USB cable.
- If the board draws more power than the USB connecter can handle, it may cycle during the boot process. In this case, connect the 5V power supply to your board.
- Start minicom on your host machine in configuration mode. As root:
# minicom -o -s -w
- A menu of configuration should appear. Use the Down-arrow key to scroll down and select the Serial port setup option, and press Enter.
- Verify that the listed serial port is the same one that is connected to the target board. If it is not, press A, and enter the correct device. This is /dev/ttyUSB0 on most Linux distributions.
- Set the Bps/Par/Bits option by pressing the letter E and using the next menu to set the appropriate values. You press the key that corresponds to the value 115200, then press Enter.
- Set Hardware flow control to No using the F key.
- Set Software flow control to No using the G key.
- Press Enter to return to the main configuration menu, and then press Esc to exit this menu.
- Reset the board, and wait for a moment. If you do not see output from the board, press Enter several times until you see the prompt. If you do not see any output from the board, and have verified that the serial terminal connection is setup correctly, contact your board vendor.
TIP: If you experience an error similar to Device /dev/ttyUSB0 is locked when starting minicom, it usually means that another process is using the serial port (which is usually another instance of minicom). You can find the process that is currently using the serial port by executing the following:
PID TTY STAT TIME COMMAND
28923 pts/0 S+ 0:00 minicom
This process can also be killed directly with fuser as root. Please use this command with caution:
To quickly connect to a board using Gnu Screen, execute the following:
For more information about using screen, please consult the man page, or view the manual online at http://www.gnu.org/software/screen/manual/screen.html
Before you begin, you should determine the name of your SD card on your host system. To do so:
- Connect the SD card to your host system. Many modern systems have SD card slots on the case, or you can purchase a USB SD Card Reader for around $15 US.
- Determine the device name of the SD Card. This can be done using dmesg. In the following example, the device is /dev/sdX, which contains one partition sdX1.
$ dmesg | tail
[88050.184080] sd 4:0:0:0: [sdX] 1990656 512-byte hardware sectors: (1.01 GB/972 MiB)
[88050.184821] sd 4:0:0:0: [sdX] Write Protect is off
[88050.184824] sd 4:0:0:0: [sdX] Mode Sense: 03 00 00 00
[88050.184827] sd 4:0:0:0: [sdX] Assuming drive cache: write through
[88050.185575] sd 4:0:0:0: [sdX] 1990656 512-byte hardware sectors: (1.01 GB/972 MiB)
[88050.186323] sd 4:0:0:0: [sdX] Write Protect is off
[88050.186325] sd 4:0:0:0: [sdX] Mode Sense: 03 00 00 00
[88050.186327] sd 4:0:0:0: [sdX] Assuming drive cache: write through
[88050.186330] sdX: sdX1
- Unmount the partition if it was automounted by using the umount command.
$ umount /dev/sdX1
- As root, run the fdisk utility on the drive.
$ sudo fdisk /dev/sdX
- In fdisk, Delete the existing partition table and create a new one using the o command.
Command (m for help): o
Building a new DOS disklabel with disk identifier 0x8b025602.
Changes will remain in memory only, until you decide to write them.
After that, of course, the previous content won't be recoverable.
- Create a new primary partition using the n command. The first partition will be a FAT partition for storing the boot files. 64 MB is typically more than enough for this purpose.
Command (m for help): n
p primary (0 primary, 0 extended, 4 free)
Select (default p): p
Partition number (1-4, default 1): 1
First sector (2048-30679039, default 2048):
Using default value 2048
Last sector, +sectors or +sizeK,M,G (2048-30679039, default 30679039): +64M
- Set the first partition as W95 FAT32 (LBA) using the t command and entering the Hex code c.
Command (m for help): t
Selected partition 1
Hex code (type L to list codes): c
- Set the bootable flag on the first partition using the a command.
Command (m for help): a
Partition number (1-4): 1
- Create a second primary partition using the n command. This partition will be a linux partition for storing the root filesystem. It will fill the rest of the SD card.
Command (m for help): n
p primary partition (1-4)
Partition number (1-4, default 2): 2
First sector (133120-30679039, default 133120):
Using default value 18432
Last sector, +sectors or +sizeK,M,G (133120-30679039, default 30679039):
Using default value 30679039
- Verify that the partition table is correct by using the p command. It should look similar to the following:
Command (m for help): p
Disk /dev/sdX: 15.7 GB, 15707668480 bytes
64 heads, 32 sectors/track, 14980 cylinders, total 30679040 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disk identifier: 0x6eaae8f8
Device Boot Start End Blocks Id System
/dev/sdX1 * 2048 133119 65536 c W95 FAT32 (LBA)
/dev/sdX2 133120 30679039 14773960 83 Linux
- This step will destroy all data on the SD Card - Write the partition table to the card using the w command.
Command (m for help): w
The partition table has been altered!
Calling ioctl() to re-read partition table.
WARNING: If you have created or modified any DOS 6.x
partitions, please see the fdisk manual page for additional
- Format the first partition of the SD card with a FAT filesystem using the mkfs.vfat tool.
$ sudo /sbin/mkfs.vfat -n boot /dev/sdX1
- Format the second partition using an ext4 filesystem using the mkfs.ext4 tool.
$ sudo /sbin/mkfs.ext4 -L rfs /dev/sdX2
Once you have a properly partitioned SD card, you can then populate it with the boot files generated by Factory.
- The partitions are usually automounted under /media, but if not, you can use the mount command to mount the partition to an arbitrary location.
$ sudo mount /dev/sdX1 /media/boot
$ sudo mount /dev/sdX2 /media/rfs
- Copy the u-boot MLO and u-boot bootloader images into the vfat partition.
$ sudo cp MLO /media/boot/
$ sudo cp u-boot.img /media/boot/
- Copy the kernel image into the boot partition.
$ sudo cp uImage-4.1-ts-armv7l /media/boot/
- Copy the dtbfile, beaglebone_black.dtb into the boot partition.
$ sudo cp beaglebone_black.dtb /media/boot/
- As root, extract the rootfs.tar.gz archive to the ext4 partition.
$ sudo tar xzf rootfs.tar.gz -C /media/rfs
- Unmount all partitions.
$ sudo umount /dev/sdX1
$ sudo umount /dev/sdX2
- Remove the card from the host machine, and insert it into the SD card slot on the BeagleBone Black.
- Hold down S2, then power up the board by removing power and reapplying it.
On the target, set the following environment variables:
|bootargs||console=ttyS0,115200 root=/dev/mmcblk0p2 rw rootwait|
|load_kernel||fatload mmc :1 0x82000000 uImage-4.1-ts-armv7l|
|load_dtb||fatload mmc :1 0x88000000 beaglebone_black.dtb|
|bootcmd||mmc rescan\; run load_kernel load_dtb\; bootm 0x82000000 - 0x88000000|
> setenv load_kernel fatload mmc :1 0x82000000 uImage-4.1-ts-armv7l
> setenv load_dtb fatload mmc :1 0x88000000 beaglebone_black.dtb
> setenv bootcmd mmc rescan\; run load_kernel load_dtb\; bootm 0x82000000 - 0x88000000
> fatload mmc :1 0x82000000 uImage-4.1-ts-armv7l
3008612 bytes read
> fatload mmc :1 0x88000000 beaglebone_black.dtb
24612 bytes read
## Booting kernel from Legacy Image at 0x82000000 ..
Image Name: Linux-4.1
Image Type: ARM Linux Kernel Image (uncompressed)
Data Size: 3008548 Bytes = 2.9 MB
Load Address: 80008000
Entry Point: 80008000
Verifying Checksum ... OK
Loading Kernel Image ... OK
## Flattened Device Tree blob at 0x88000000
Booting using the fdt blob at 0x88000000
Loading Kernel Image ... OK