AM625: AM625: Booting Linux from U-Boot via Network with SCP or FTP Support

yulong zhang

Part Number: AM625
Other Parts Discussed in Thread: SK-AM62B

We are developing with the AM625. Our hardware only has a serial port and an Ethernet port, with no USB or SD card interfaces.

We encountered an issue when flashing Linux to the eMMC: the Linux system booted via the network lacks the necessary tools to flash the eMMC. Specifically, it is missing partitioning tools, as well as SSH or FTP transfer services.

Specific Operations:

(1) We boot the system by transferring the device tree, kernel, and root filesystem via TFTP in U-Boot.

The root filesystem used is ramfs: tisdk-tiny-initramfs-am62xx-evm.rootfs.cpio.

However, this ramfs does not include tools like mkfs, nor does it have SSH or FTP services. As a result, we cannot format the eMMC or solidify the system to the eMMC using network transfer methods.

Do you have a solution for the issue we are facing?

Our goal is: After booting U-Boot, we want to flash files such as the filesystem and kernel to the eMMC via Ethernet, just like using an SD card.

11 天前

0 Taylor 10 天前

TI__Mastermind 38805 points

Hi,

We have received your post and the investigation will take some time. Thank you for your patience.

0 Vivian Gao 9 天前

TI__Mastermind 39820 points

After booting u-boot, to flash to eMMC via Ethernet on SK-AM62x, You have to convert your specific root filesystem tisdk-tiny-initramfs-am62xx-evm.rootfs.cpio. into a single ext4 image file (.ext4 or .img) on your Linux host PC.

you must first extract the contents of the CPIO archive. You cannot treat a .cpio file like a compressed .tar.xz file directly.

The procedure requires three main phases:

Extraction: Unpacking the CPIO archive into a temporary directory.
Creation: Making an empty .ext4 image file.
Population: Copying the extracted files into the new .ext4 image file.

General steps are as below:-

cd <path-ti-psdk>/filesystem
dd if=/dev/zero of=rootfs.ext4 bs=1M count=2000
mkfs.ext4 -F rootfs.ext4
mkdir -p mnt_fs
sudo mount -t ext4 -o loop rootfs.ext4 mnt_fs

mkdir -p extracted_rootfs
cd extracted_rootfs
sudo cpio -idmv < ../tisdk-tiny-initramfs-am62xx-evm.rootfs.cpio
sudo cp -a extracted_rootfs/. mnt_fs/
sudo umount mnt_fs
sudo cp rootfs.ext4 /tftpboot/

For more information, Could you please refer the section under How to flash to eMMC via Ethernet on SK-AM62B/ SK-AM62A of below FAQ

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1328520/faq-how-to-boot-sk-am62b-sk-am62a-via-ethernet-and-flash-u-boot-and-linux-binaries-into-emmc-via-ethernet

0 yulong zhang 8 天前回复 Vivian Gao

Prodigy 80 points

We need to include the mkfs.ext4 tool and SSH and SCP services in the cpio filesystem. However, they are not present by default. How can we add them?

0 Vivian Gao 7 天前回复 yulong zhang

TI__Mastermind 39820 points

I suggest you use NFS rootfs as the flashing Linux instead of transferring the tiny rootfs.cpio to the board, then you can use the sdk "base" or "default" rootfs using NFS, which will have all the tools included.

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AM625: AM625: Booting Linux from U-Boot via Network with SCP or FTP Support

Specific Operations: