How can I boot the rootfs readonly?

[blangero_wang]

Hi:

     I want to load rootfs readonly on my imx6q, the rootfs is debian_armhf.

     In uboot I set the args as:

     setenv bootargs_mmc 'setenv bootargs ${bootargs} root=/dev/mmcblk1p1 rootwait ro video=mxcfb0:dev=lcd,1440x900,if=RGB24'

     and I do get verbose in bootup:

     EXT3-fs (mmcblk1p1): mounted filesystem with writeback data mode

     VFS: Mounted root (ext3 filesystem) readonly on device 179:25.

     But in the system I still get rw in mtab and the rootfs is still writable.

     How can I solve it?

     Thanks!

[katherrafi]

Hope this may help to make the read only in fstab.

/dev/root         /      auto      remount,ro      1    1

[Raana]

Hi Kather Rafi,

Even I've tried the same in boot arguments, but failed. So, I've tried with fstab and it's working fine.
May I know, 
Why 'ro' is not working in boot arguments ?
Is this related to NXP or default uboot or something ?
Whether 'fstab' is the only way or fine way to make rootfs as 'ro' ?

Thank You.

Best Regards,

J.P.Raja

[blangero_wang · Accepted solution]

I got it resolved.

It's the fstab file which defines the readonly, but not uboot args.

[Raana]

Hi Blangero Wang,

Even I've tried the same in boot arguments, but failed. So, I've tried with fstab and it's working fine.
May I know,
Why 'ro' is not working in boot arguments ?
Is this related to NXP or default uboot or something ?
Whether 'fstab' is the only way or fine way to make rootfs as 'ro' ?

Thank You.

Best Regards,

J.P.Raja

[shaoxiao_guo_dn]

Do you know why now?