Hi team,
The customer is looking for an easy and approachable way of updating their Colibri iMX6ULL whole flash memory without the use of a PC connection, pretty much just a USB drive, where they will have the new files (Uboot, DTB, kernel, rootfs) and the serial console. As you know, we would have to tackle 2 steps: first backup the files, and then restore them to another module.
I made some changes but I couldn’t find an easy way to do it, but maybe (hopefully) I’m missing something.
I’ve been trying the following approaches to do, with the limitations given, in ascending difficulty level:
Backup the mtd partitions directly from a running Linux.
With cat /proc/mtd and mtdparts, I could get an idea of the flash partitioning. I tried to backup the “least sensitive data” first, mtd4, which contained the rootfs within the ubifs.
Uboot:
Colibri iMX6ULL # mtdparts
device nand0 <gpmi-nand>, # parts = 5
#: name size offset mask_flags
0: mx6ull-bcb 0x00080000 0x00000000 0
1: u-boot1 0x00180000 0x00080000 1
2: u-boot2 0x00180000 0x00200000 1
3: u-boot-env 0x00080000 0x00380000 0
4: ubi 0x1fc00000 0x00400000 0
Linux:
root@colibri-imx6ull:~# cat /proc/mtd
dev: size erasesize name
mtd0: 00080000 00020000 "mx6ull-bcb"
mtd1: 00180000 00020000 "u-boot1"
mtd2: 00180000 00020000 "u-boot2"
mtd3: 00080000 00020000 "u-boot-env"
mtd4: 1fc00000 00020000 "ubi"
I tried with dd if=/dev/mtd4 of=/media/sda1/mtd4.backup count=508 bs=1M (1fc00000 = 508MB), which succeeded, but I couldn’t restore it back. I tried through TEZI’s Linux to restore it back before launching a ramdisk or a Linux from a USB but that directly failed (TEZI has an additional MTD partition loaded):
/ # cat /proc/mtd
dev: size erasesize name
mtd0: 20000000 00020000 "gpmi-nand"
mtd1: 00080000 00020000 "mx6ull-bcb"
mtd2: 00180000 00020000 "u-boot1"
mtd3: 00180000 00020000 "u-boot2"
mtd4: 00080000 00020000 "u-boot-env"
mtd5: 1fc00000 00020000 "ubi"
/ # flash_erase /dev/mtd5 --quiet 0 0
/ # cat /media/mtd4.backup | nandwrite --quiet --pad /dev/mtd5
libmtd: error!: bad eraseblock number 4064, mtd5 has 4064 eraseblocks
nandwrite: error!: /dev/mtd5: MTD get bad block failed
error 22 (Invalid argument)
nandwrite: error!: Data was only partially written due to error
error 22 (Invalid argument)
Using a Legacy image for the iMX6ULL (But there is no Legacy flashing method for the ULL)
Before going deeper and starting to implement a “manual TEZI” (basically, do all the steps that TEZI will do in this equivalent case, like going through all the UBI commands) or find more information about DFU, I wanted to ask you about the possibility in launching TEZI without having to go to the recovery mode. I went through the following ideas:
- Creating a TEZI partition, launchable through U-boot. For this, I added tezi.itb in my image folder and then made some image.json formats additions (adding a new UBI volume and creating a new MTD device). Both methods failed (I can give the log but I don’t want to make this post too long, so tell me if you think it will help) during the flashing, size or format related.
- Creating a TEZI launchable USB. As a try, I followed “Boot From an SD Card / USB Stick / SATA drive” to create the TEZI USB but Uboot didn’t seem to recognize it.
Any suggestion will be appreciated!
Many thanks and best regards,
Alvaro.
