Not enough free space in your /mnt/system

[m93a]

I did a fresh LineageOS install on OnePlus Nord, then I tried sideloading MinMicroG via the LineageOS Recovery, and the script failed with:

Doing size checks...

!!! FATAL ERROR: Not enough free space in your /mnt/system

Stopping installation and Uninstalling...

Installation failed!
ERROR:    recovery: Error in /sideload/package.zip (status 1)

Installation completed with status 1.
Installation aborted.

[m93a]

This is the output of adb shell df while in Recovery:

adb shell df                                             
Filesystem     1K-blocks  Used Available Use% Mounted on
rootfs           3626120 30784   3595336   1% /
tmpfs            3782352  1688   3780664   1% /dev
tmpfs            3782352     0   3782352   0% /mnt
tmpfs            3782352     0   3782352   0% /apex
tmpfs            3782352     4   3782348   1% /linkerconfig
tmpfs            3782352    68   3782284   1% /tmp
tmpfs            3782352     0   3782352   0% /storage

and while booted to the system:

Filesystem        1K-blocks    Used Available Use% Mounted on
/dev/block/dm-17     921644  849208     56052  94% /
tmpfs               3782352    1792   3780560   1% /dev
tmpfs               3782352       0   3782352   0% /mnt
/dev/block/dm-18     434168  374104     50804  89% /system_ext
/dev/block/dm-16    1010748  427728    566636  44% /product
/dev/block/dm-19     842548  840024         0 100% /vendor
/dev/block/dm-15      63084   62888         0 100% /odm
tmpfs               3782352      16   3782336   1% /apex
/dev/block/dm-47  105658828 1999280 103528476   2% /data
... (some /apex/ entries)
/dev/fuse         105658828 1999280 103528476   2% /storage/emulated

[FriendlyNeighborhoodShane]

Hi, sorry for the late reply.

It's pretty much as it says. I suspect /dev/block/dm-17 is your system partition, and you have either 56mb or 28mb space free in it (df's behaviour without the -P or -h flags is not standardised, IDK how the android one behaves), either of which is too low for microG and friends these days. If you save the recovery log after flashing it, the installer script logs (in more clearer units) how much space it wants and how much it finds.

But really, what this essentially means is that you're using a dynamic partition device, where your partitions are sized almost exactly to fit whatever the ROM includes and nothing more. You'll need to ask your ROM maintainer to expand that free space, if only for the vanilla/nogapps variant:
#19 (comment)