TFTP Boot

tftpboot is a boot command in U-boot for booting devices over a network using the Trivial File Transfer Protocol (TFTP).

Genio 1200-EVK supports the Ethernet driver in U-Boot since IoT Yocto v24.0. Genio 510/700-EVK supports the Ethernet driver in U-Boot since IoT Yocto v24.1. It also provides support for booting via tftpboot natively in U-Boot.

There are many tutorials and how-to guides for tftpboot with U-Boot available on the Internet and on YouTube. Here, we provide a very simple example of network setup for tftpboot on U-Boot.

Prepare TFTP Server on PC Host

There are many TFTP server software options for Windows or Linux PC hosts. Developers will need a TFTP server on the PC host and prepare the image for the target EVK. For example, we suggest tftpd64 for Windows PC hosts, and tftpd for Linux PC hosts. Please refer to the documentation of these software for server settings and how to place the test.image in the folder accessible by the TFTP server.

Configuration Example

After user install the TFTP server, please ensure that the Ethernet of Genio 1200-EVK and the PC host are in the same LAN network with the same IPv4 subnet. In the following example, the IP address of the PC host is 192.168.0.111, and the IP address of Genio 1200-EVK is 192.168.0.100. Prepare the test.image in the folder controlled by the TFTP server.

  1. Enter the U-Boot shell on Genio 1200-EVK.

  2. Input the following commands for network settings and check the network connection:

setenv serverip 192.168.0.111
setenv ipaddr 192.168.0.100
setenv gatewayip 192.168.0.255
setenv netmask 255.255.255.0
setenv ethaddr 08:00:00:00:22:01
ping 192.168.0.111

Developers should see the following output:

=> ping 192.168.0.111
Using ethernet@11021000 device
host 192.168.0.111 is alive

Transfer Test Image to Genio EVK

  1. Transfer test.image from the PC host to Genio 1200-EVK:

=> tftpboot test.image
Using ethernet@11021000 device
TFTP from server 192.168.0.111: our IP address is 192.168.0.100
Filename 'test.image'.
Load address: 0x4c000000
Loading: ##################################################################
         ##################################################################
         ##########################################################
         11.4 MiB/s
done
Bytes transferred = 104857600 (6400000 hex)

Now, the user have transferred test.image to the address 0x4c000000. If this is a fitImage, you can use the command bootm to boot the Linux kernel from this fitImage. However, user need to take care of many other settings, such as loading the device tree blob (DTB), etc. Please read the U-Boot script carefully and modify it as needed to ensure a successful boot.

Build and Deploy rity-bringup-image via TFTP Boot on Genio EVK

Developer could build the rity-demo-image and then boot the kernel and mount the file system via ramdisk on Genio EVK. However, The transmission time when deploying via tftpboot will be very long due to the size of the rity-demo-image. Instead, we recommend using the rity-bringup-image to try this feature, which is more suitable given the memory limitations and reduce the network transmission time.

Note

The Genio 510-EVK has only 4GB of RAM, which is insufficient to handle the size of the rity-demo-image

Kernel Configuration

Enabling CONFIG_BLK_DEV_RAM=y is vital for supporting ramdisk block devices, as it simplifies the TFTP boot process by facilitating quick and flexible access to a temporary root filesystem. IoT Yocto has already enabled this configuration since version 24.1. If you want to use alternative approaches such as initramfs, please ensure that you configure them properly according to your design specifications.

CONFIG_BLK_DEV_RAM=y

Instructions to Build rity-bringup-image

Edit your conf/local.conf to include necessary settings for using ramdisk rootfs with rity-bringup-image.

IMAGE_FSTYPES:append = " cpio.gz.u-boot "

Build the rity-bringup-image:

MACHINE=genio-1200-evk bitbake rity-bringup-image

Instructions to Delopy and Use TFTP Boot with Ramdisk of rity-bringup-image

Once the build is complete, locate the output files, which are typically found in the tmp/deploy/images/ directory within the corresponding MACHINE folder. For exampel, if user wants to boot Genio 1200-EVK via TFTP Boot. Then, deploy the two required files fitImage and root filesystem rity-bringup-image-genio-1200-evk.cpio.gz.u-boot to the TFTP server.

Important

Please aware the EVK should have a well function boot chain on the main storage (EMMC or UFS) to support TFTP boot. If user is unsure whether the firmware supports TFTP boot, please flash the new build rity-bringup-image on the EVK.

  1. Run the following command to reboot the system:

reboot

2.Hit any key when you see the message “Hit any key to stop autoboot”

3.Run the following commands in u-boot mode:

setenv ethaddr 08:00:00:00:22:01
setenv bootfile fitImage
setenv serverip XXX.XXX.XXX.XXX  # The IP address of your TFTP server
setenv bootargs "root=/dev/ram0 rootwait ramdisk_size=1207185408 ramdisk_start=0x68000000"
saveenv

4.Hit any key when you see the message “Hit any key to stop autoboot”

5.Run the following commands in u-boot mode:

dhcp
tftpboot 0x68000000 rity-bringup-image-genio-1200-evk.cpio.gz.u-boot

It will take several minutes, depends on the image size and network transmission. Then we could boot the kernel using fitImage.

bootm 0x4c000000 0x68000000