Yocto EMMC Burning TI
This page is using the default release am62-yocto-dunfell-5.10.168_08.06.00.42-v1.0.
To view this page for a specific Variscite SoM and software release, please follow these steps:
- Visit variwiki.com
- Select your SoM
- Select the software release
Introduction
The VAR-SOM-AM62 can boot from an SD card or from internal storage.
The Variscite VAR-SOM-AM62 comes with eMMC, which holds U-Boot, the kernel image and the ext4 root file system.
eMMC structure
The eMMC has the following structure:
| Offset Address | Offset (MiB) | Size |
Partition |
Description |
|---|---|---|---|---|
| 0x0 | 0 | 1 MiB | Reserved | Reserved |
| 0x100000 | 1 MiB |
128 MiB | Boot | Boot partition containing U-Boot images |
| 0x8600000 | 134 MiB | 1 MiB | U-Boot Env | Reserved for U-Boot environment. |
| 0x8700000 | 135 MiB | Rest of eMMC | rootfs |
An ext4 partition containing the root file system (including Linux image and the device tree blobs under /boot |
For example, an 16 GiB eMMC has the following layout:
root@am62x-var-som:~# fdisk -l /dev/mmcblk0 Disk /dev/mmcblk0: 14.69 GiB, 15758000128 bytes, 30777344 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 Disklabel type: dos Disk identifier: 0xe3dbe120 Device Boot Start End Sectors Size Id Type /dev/mmcblk0p1 * 2048 264191 262144 128M c W95 FAT32 (LBA) /dev/mmcblk0p2 276480 30777343 30500864 14.6G 83 Linux
Installing the Yocto binaries
If you followed the Create a Recovery SD card steps, the Yocto binaries and the flashing scripts will be included in your SD card.
The flashing scripts are easy-to-use example scripts for flashing images into NAND flash / eMMC.
There is also a section below describing how to flash the images manually.
Images Locations
The following is the directory structure of the SD card, which includes the installation scripts and files for installation:
/usr/bin/install_yocto.sh /usr/bin/echos.sh /opt/images/Yocto/ /opt/images/Yocto/boot /opt/images/Yocto/boot/u-boot.img /opt/images/Yocto/boot/tiboot3.bin /opt/images/Yocto/boot/tispl.bin /opt/images/Yocto/boot/uEnv.txt /opt/images/Yocto/rootfs.tar.zst