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change mtdparts organization, but device still boot up successfully

Question asked by Steven Yu on Apr 16, 2017
Latest reply on Apr 17, 2017 by Steven Yu

Hi,

 

It is a strange situation as in attach log file.

 

The first time device boot up using below mtdparts parameter, and the kernel show related mtd organization.

bootargs=console=ttymxc0,115200 ubi.mtd=3 root=ubi0:rootfs rootfstype=ubifs mtdparts=gpmi-nand:64m(boot),16m(kernel),16m(dtb),-(rootfs)

......

Creating 4 MTD partitions on "gpmi-nand":
0x000000000000-0x000004000000 : "boot"
0x000004000000-0x000005000000 : "kernel"
0x000005000000-0x000006000000 : "dtb"
0x000006000000-0x000008000000 : "rootfs"

.......

root@imx6ull14x14evk:~# cat /proc/mtd
dev: size erasesize name
mtd0: 04000000 00020000 "boot"
mtd1: 01000000 00020000 "kernel"
mtd2: 01000000 00020000 "dtb"
mtd3: 02000000 00020000 "rootfs"
root@imx6ull14x14evk:~#

 

Then, we only modify mtdparts as below and reboot device. However, the device still can boot up successfully using new mtd organization. How can device figure out the original position of kernel/dtb/rootfs in flash ? Any idea?  

 

=> setenv bootargs 'console=ttymxc0,115200 ubi.mtd=3 root=ubi0:rootfs rootfstype=ubifs mtdparts=gpmi-nand:2m(boot),16m(kernel),2m(dtb),-(rootfs)'
=> saveenv
=> print

......

bootargs=console=ttymxc0,115200 ubi.mtd=3 root=ubi0:rootfs rootfstype=ubifs mtdparts=gpmi-nand:2m(boot),16m(kernel),2m(dtb),-(rootfs)

......

 

Creating 4 MTD partitions on "gpmi-nand":
0x000000000000-0x000000200000 : "boot"
0x000000200000-0x000001200000 : "kernel"
0x000001200000-0x000001400000 : "dtb"
0x000001400000-0x000008000000 : "rootfs"

......

root@imx6ull14x14evk:~# cat /proc/mtd
dev: size erasesize name
mtd0: 00200000 00020000 "boot"
mtd1: 01000000 00020000 "kernel"
mtd2: 00200000 00020000 "dtb"
mtd3: 06c00000 00020000 "rootfs"

 

Regards,

Steven Yu

Original Attachment has been moved to: change_partition_size_stillbootup.txt.zip

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