OpenWrt/LEDE Project

  • Status Unconfirmed
  • Percent Complete
  • Task Type Bug Report
  • Category Base system
  • Assigned To No-one
  • Operating System All
  • Severity Medium
  • Priority Very Low
  • Reported Version Trunk
  • Due in Version Undecided
  • Due Date Undecided
  • Private
Attached to Project: OpenWrt/LEDE Project
Opened by Hadmut Danisch - 20.04.2020

FS#3026 - confusion in device names / non-expandable partition


I’m currently installing OpenWRT from

(latest version) on a Banana Pi Router 1, copied the imaga on an 8GB micro sd card.

At a first glance, everything seems running well.

But since the available disk space is limited to about 256 MB, while the sd card has 8GB, I tried to expand the writeable partition.

On the sd card, I do see two partitions:

  • First: A vfat containing boot.scr dtb uImage
  • Second: a ro squashfs with the operating system

I did not see what’s mounted as the writable overlay. Expanding the second partition to the full sd card limit didn’t change available disk space.

When looking at the running system, things get really confusing and seem broken.

The first partition (vfat) does not seem to be mounted at all (not problem, since not needed after boot).

The second partition seems to be mounted twice:

* there’s a /dev/root mounted to /rom as a squashfs. Although there is no /dev/root entry and I did not see any way to find what’s root, this must be that second partition containing a squashfs file system.

* there’s a /dev/loop0 mounted to /overlay as f2fs , obviously the writable partition.

But then, losetup shows that /dev/loop0 is set on the ‘file’ /mmcblk0p2 , which does not exist. /dev/mmcblk0p2 on the other hand, is the second partition already mounted as squashfs to /rom.

So there’s three problems:

  1. The boot process mounts some devices, but uses device names not compliant with the /dev file system and as such not comprehensible/debuggable.
  2. The boot process seems to mount the same partition as squashfs on /rom and as f2fs on /overlay . That’s broken by design. If that overlay uses some sort of offset or whatever, it should use a third partition.
  3. It’s not obvious where on the sd card the writable data (overlay) is stored and how to expand free disk space.
Hadmut Danisch commented on 20.04.2020 13:04

Yeah, it uses an Offset and hangs after the squashfs in the same partition.

What is that good for? Why not a third partition on it's own?


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