How to make rootfs writable?

[jie-ss]

Currently I'm using nand flash as the storage device, I found the rootfs used 100% space as below.
I guess the rootfs is read-only, just wonder can we set the rootfs to writable, or even better that split the nand to two blocks: one is read-only for image file, and the other block is writable ?

df

Filesystem 1K-blocks Used Available Use% Mounted on
ubi0:rootfs 86244 86244 0 100% /
devtmpfs 71848 0 71848 0% /dev
tmpfs 72584 0 72584 0% /dev/shm
tmpfs 72584 64 72520 0% /tmp
tmpfs 72584 16 72568 0% /run

[schung1218]

Hi jie-ss,
I use numaker_som_ma35d16a81_defconfig in the buildroot and run it on the Numker-HMI board as follow.
NOTE: modified boot configuration to boot from nand in the defconfig

df

Filesystem 1K-blocks Used Available Use% Mounted on
ubi0:rootfs 70760 13508 57252 19% /
devtmpfs 71848 0 71848 0% /dev
tmpfs 72584 0 72584 0% /dev/shm
tmpfs 72584 60 72524 0% /tmp
tmpfs 72584 16 72568 0% /run

I want to know the detailed steps in the buildroot,

[jie-ss]

what I done:

1. clone this repo.
2. make numaker_som_ma35d16a81_defconfig
3. make menuconfig and add some Qt5 modules
4. make
5. make menuconfig and change to ma35d1_nand
6. make arm-trusted-firmware-dirclean uboot-dirclean linux-dirclean optee-os-dirclean
7. make

there is a warning, don't know is it related:
ubi0 warning: ubi_eba_init: cannot reserve enough PEBs for bad PEB handling, reserved 25, need 160

the log:
nand.txt

[schung1218]

Hi jie-ss,
Because Qt5 is a large library, Qt5 library exceeds the UBI default size. So, you may need to disable qt5 library
,or adjust UBI size as referenced in the FAQ_MA35_Family_NAND Flash Rootfs Size