Shrink boot partition on SD card

[Echo]

Hi,

following the documentation, I used

nand-sata-install

to

• boot from SD, system on SATA / USB

without any problems. My backup solution (raspiBackup.sh) now creates a 16GB image for the SD card, even if it is just used to boot.

Is it possible to shrink the partition?

 

Thank you

René

[martinayotte]

Here is how to shrink an existing image.

In "gparted", do "edit/resize" of the partition, but leave a certain percentage of free space, then "Apply".

Replace the "endsect" by the actual number shown by fdisk.

sudo modprobe loop
sudo losetup -f
sudo losetup /dev/loop0 myimage.img
sudo partprobe /dev/loop0
sudo gparted /dev/loop0
sudo losetup -d /dev/loop0
fdisk -l myimage.img
truncate --size=$[(endsect+1)*512] myimage.img

[Echo]

If I understand correctly, the steps apply to the already taken backup img file.

After shrinking, I could write it to another SD card and test if the root partition is smaller, correct?

 

Thank you

[martinayotte]

Right ! This method could also be used when you wish to re-install a small image on smaller SDCard.

[Echo]

Thanks. I though it might be possible to shrink while the system is running, but this is a way I can live with.

[Echo]

I'm still working on this issue.

In the documentation I found that it is possible to specify a size in percentage, that is used to adjust the sd card partition:

I put 25% in the file /root/.rootfs_resize

Then I wanted to run the firstrun script again to apply the change (and create a new ssh key).

But the file is not present on my disk. However I found it under /media/mmc/etc/init.d. I am running "ARMBIAN 5.25 stable Debian GNU/Linux 8 (jessie) 3.4.113-sun8i".

 

Is the file supposed to be missing after the initial resize and copying everything to the hdd?