Chroot into Raspberry Pi ARMv7 Image with Qemu

raspberry-pi-chroot-armv7-qemu.md

# install dependecies
apt-get install qemu qemu-user-static binfmt-support

# download raspbian image
wget https://downloads.raspberrypi.org/raspbian_latest

# extract raspbian image
unzip raspbian_latest

# extend raspbian image by 1gb
dd if=/dev/zero bs=1M count=1024 >> 2016-05-27-raspbian-jessie.img

# set up image as loop device
losetup /dev/loop0 2016-05-27-raspbian-jessie.img

# check file system
e2fsck -f /dev/loop0p2

#expand partition
resize2fs /dev/loop0p2

# mount partition
mount -o rw /dev/loop0p2  /mnt
mount -o rw /dev/loop0p1 /mnt/boot

# mount binds
mount --bind /dev /mnt/dev/
mount --bind /sys /mnt/sys/
mount --bind /proc /mnt/proc/
mount --bind /dev/pts /mnt/dev/pts

# ld.so.preload fix
sed -i 's/^/#/g' /mnt/etc/ld.so.preload

# copy qemu binary
cp /usr/bin/qemu-arm-static /mnt/usr/bin/

# chroot to raspbian
chroot /mnt /bin/bash
	# do stuff...
	exit

# revert ld.so.preload fix
sed -i 's/^#//g' /mnt/etc/ld.so.preload

# unmount everything
umount /mnt/{dev/pts,dev,sys,proc,boot,}

# unmount loop device
losetup -d /dev/loop0

---

Source

parted was just the hint I needed. For anyone that wants to resize their image properly, this is how I did it:

First, list the partitions:

$ sudo parted 2016-05-27-raspbian-jessie.img print

Model:  (file)
Disk /home/pop_desktop/workspace/raspiblitz_ci/2021-03-04-raspios-buster-arm64.img: 3729MB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags: 

Number  Start   End     Size    Type     File system  Flags
 1      4194kB  273MB   268MB   primary  fat32        lba
 2      273MB   3729MB  3456MB  primary  ext4

Use this to determine the partition number you want, and the "end" of the partition. I wanted partition 2, as that's the home partition that needs to grow.

Then grow the partition like so:

loop=$(losetup -f)  # Find the first available loop device

# extend raspbian image by 1gb
dd if=/dev/zero bs=1M count=1024 >> raspios.img
sudo parted raspios.img resizepart 2 4700MB

# set up image as loop device
losetup -P $loop raspios.img

# check file system
e2fsck -y -f ${loop}p2

#expand partition
resize2fs ${loop}p2

In the above example, I changed the "end" of the ext4 partition to 4700MB, roughly increasing it by 1GB.