Downloading u-boot, dtb, kernel and rootfs to eMMC using uboot commands

[ssuresh]

Hi NXP,

[REQUIREMENT]

We will boot the imx8mplus board using SD Card.

From SD Card bootloader, we need to load  uboot, dtb, kernel and rootfs to RAM using tftp and then write it to the eMMC.

We were successful in loading kernel and dtb. Commands used are:

tftp 0x40400000 Image

tftp 0x43000000 imx8mp-evk-revb4.dtb

fatwrite mmc 2:1 0x40400000 Image 1e82a00

fatwrite mmc 2:1 0x43000000 imx8mp-evk-revb4.dtb 15d94

But stuck with uboot and rootfs. Can you please share the steps to achieve this?

Thanks!

[ssuresh]

Referred the doc but could'nt see the steps to flash uboot and rootfs to emmc from uboot prompt.

From the docs, it says the uboot image is u-boot.imx, but cant find such an image after the compilation of sdk.

Also, can you please give us some more clarity on the blk and cnt parameter calculation? mmc write command is not working properly and leading to crash.

[joanxie]

what's your detailed demands? do you need download images to your board via network? do you need download to SD card or emmc?  why do you need download images via network? just for easy to download or your board couldn't support uuu tools?

[ssuresh]

Hi NXP Team,

Our end product cannot be flashed via USB using uuu tool. Thus to support future firmware upgrades, our only option is to boot the device from SD Card, from SD card bootloader, download the new firmware (uboot, kernel, dtb and rootfs) to eMMC and put the device back to eMMC boot mode (default boot mode is via eMMC)

Hope this clarifies the queries

Thanks!

[joanxie · Accepted solution]

firstly you can use dd command to download the images to the sd card(you can find the detailed command from user guide I sent to you before), then refer to the link as below, which tell you how to flash the images from sd card to emmc

https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Guide-to-flash-an-eMMC-from-SD-Card-on-i...

[Sunil_13]

Hi @joanxie ,

We are working with the i.MX8M Plus EVK, which has 32 MB QSPI flash.
Our goal is to boot U-Boot, Linux kernel, device tree, and initramfs (rootfs.img ) entirely from QSPI flash.

We are able to successfully boot:

U-Boot (from flash.bin)

Linux kernel (Image.gz)

Device Tree (imx8mp-evk.dtb)

However, we are facing issues when loading and using the initramfs/rootfs image from QSPI flash. The kernel starts successfully, but the kernel hangs at Waiting for removable media.... see the below log attached.

-----Flash Layout and Image Sizes----------------

QSPI flash size: 32 MB

flash.bin (U-Boot + SPL) ~2.3 MB
Image.gz (Kernel) ~13.5 MB
imx8mp-evk.dtb ~86 KB
rootfs.img ~12.6 MB

----QSPI Offset Layout----------
flash.bin @ 0x00000000
Image.gz @ 0x00240000
imx8mp-evk.dtb @ 0x01000000
rootfs.img @ 0x01080000

------Programming files into QSPI (from SD card)---------
sf probe 0
sf erase 0x0 0x2000000

fatload mmc 1 ${loadaddr} flash.bin
sf write ${loadaddr} 0x0 ${filesize}

fatload mmc 1 ${loadaddr} Image.gz
sf write ${loadaddr} 0x240000 ${filesize}

fatload mmc 1 ${loadaddr} imx8mp-evk.dtb
sf write ${loadaddr} 0x1000000 ${filesize}

fatload mmc 1 ${loadaddr} rootfs.img # initramfs (cpio.gz)
sf write ${loadaddr} 0x1080000 ${filesize}

------After flashing,power-cycle the board--------------

After boot from u-boot,setting the env variables for Linux kernel (Image.gz),Device Tree (imx8mp-evk.dtb),rootfs.img.

sf probe 0
setenv loadaddr 0x40480000 // kernel
setenv fdt_addr 0x43000000 //dtb
setenv initrd_addr 0x43800000 //rootfs
setenv kernel_comp_addr_r 0x50000000
setenv kernel_comp_size 0x04000000

sf read ${loadaddr} 0x240000 0xCD3CE2

sf read ${fdt_addr} 0x1000000 0x14360

sf read ${initrd_addr} 0x1080000 0xC04DB0

setenv bootargs "console=ttymxc1,115200 root=/dev/ram0 rw"

setenv bootcmd 'sf probe 0; sf read ${loadaddr} 0x240000 0xCD3CE2; sf read ${fdt_addr} 0x1000000 0x14360; sf read ${initrd_addr} 0x1080000 0xC04DB0; booti ${loadaddr} ${initrd_addr} ${fdt_addr}'

saveenv

-----------------------Question 1------------------------------------
1.With SD card Wic file working fine with partitions (Boot/Root).
2.We genarated Two yocto images
==> 1.bitbake core-image-minimal-initramfs (generated initramfs.cpio.gz) this cpio.gx converted into rootfs.img by using this cmd mkimage -A arm -O linux -T ramdisk -d <gzipped_rootfs> <Ramdisk_name> (from linux user guide)
==>2.Also generated tiny rootfs from yocto generated using bitbake core-image-tiny. core-image-tiny-imx8mp-evk.tar.zst this tar extracted into EXT4 partition in SD card succussfully loading tiny rootfs .
3.But as said in 2nd point rootfs.img also put into EXT4 root partition in SD card but not loading the rootfs.

-----------------------Question 2------------------------------------
1.Is this the correct approach to boot an initramfs (rootfs.img) directly from QSPI on i.MX8M Plus EVK?

-----------------------Question 3------------------------------------
3.Is there any recommended NXP reference image for booting kernel and initramfs entirely from QSPI on i.MX8MP(Linux kernel (Image.gz),Device Tree (imx8mp-evk.dtb),rootfs.img) ?

4.How can load rootfs.img from QSPI Flash ?

[ssuresh]

Thanks NXP for the detailed reply!

[joanxie]

pls refer to the chapter 4.4.1.2 Downloading an image to MMC/SD of enclosed file