File system and console differences

I have a device that I built an Openwrt image for a while back, and it was working great.
I am slowly getting used to the build and upgrade procedures :wink:
I refreshed my OpenWrt build system and built a new image for the same device. It now has a few difference that I'm not sure how to fix.

The two main differences are - i)Filesystem allocation and ii)Console port allocation.

File System
So my previous build resulted in a filesystem allocation like this:
Screenshot 2020-05-20 at 10.42.26

And my new build looks like this:
Screenshot 2020-05-20 at 11.11.54
Note that the bulk of the freespace has moved from '/' to '/rom'

Console Port
The second difference is the console port.
Mid-way through the boot it changes from ttys0 to ttyS2 - and ttysS2 is not available on my board.

So I'm guessing I have to dig into some build config files to sort these - but I wouldn't know where to start! (I am just a beginner at building with OpenWrt!)

Can anyone show my how to adjust the two things above?

You should at least tell us from which device you are speaking and what is the difference in the build config of your two self built images.


Hi @juppin - yeah sorry - here's the build device setup:
Screenshot 2020-05-20 at 12.40.18

I did a build last year on an existing buid machine I inherited from a colleague. (that's the first build in my original post).
I got a new build machine, downloaded OpenWrt again, did a build - it has the above differences.

I'm interested in how to modify the build to effect and reverse changes like the ones I have seen above.

So we are talking about the LinkIt Smart 7688, right?

1 Like

Hi @tmomas - no, it's a similar device not listed. (HLK-7688A)
But to be honest, does it matter? I'm asking for general advice on how to edit things like the file system allocations and console serial port. Surely that applies no matter what the device?

Not sure in this case, but on this side of the service desk it can be helpfull to know what $user is doing and what device he has.


The rom holds any data that is compiled in the firmware image and about 30M are a lot of stuff.
My assumption is that you have selected a lot of packages to be included in the final firmware image that you see as /rom.

On your or your friends first build there weren't that much packages preinstalled in the firmware and you have probably installed them later with opkg into the writeable overlay filesystem.

So my question about the difference was more about the selected packages for the different builds.


This is mostly related to your not official supported device. Don't expect your selected board to be compatible with your HLK-7688A.

Anyway your request device/board config is here:

Thanks - that makes sense.

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