Replacing the 32-bit Root Filesystem

Compiling Debian 11 armhf Root Filesystem

Install Required Tools

PC:~$ sudo apt install -y debootstrap

Create Root Filesystem Directory

PC:~$ mkdir rootfs

PC:~$ cd rootfs

Generate Debian 11 armhf Root Filesystem Using debootstrap

PC:~$ sudo debootstrap --arch armhf bullseye rootfs http://mirrors.tuna.tsinghua.edu.cn/debian

Switch to armhf Root Filesystem

sudo chroot rootfs bash

Install Required Packages in armhf Root Filesystem

apt update

apt install -y sudo usbutils network-managerfdisk \
vim nano openssh-server iputils-ping wget curl \
iproute2 dialog locales kmod zip unzip u-boot-tools initramfs-tools

Create User

adduser radxa

gpasswd -a radxa sudo

Flash Debian 11 arm64 Image to SD Card or eMMC Module

Record Target Device Information

Confirm Target Device

Insert the SD card or eMMC module with the newly flashed Debian 11 arm64 into your local PC and mount it

PC:~$ lsblk
sdb      8:16   1  29.3G  0 disk
├─sdb1   8:17   1    16M  0 part
└─sdb2   8:18   1   5.1G  0 part

From this, we can see our target device is /dev/sdb2

Record UUIDs

PC:~$ sudo blkid /dev/sdb2
/dev/sdb2: LABEL="rootfs" UUID="8bf96d05-7c97-42fc-863c-95e3e7603ef4" BLOCK_SIZE="4096" TYPE="ext4" PARTLABEL="rootfs" PARTUUID="474d4c1f-53da-447c-bab4-334abe0d5753"
PC:~$ sudo blkid /dev/sdb1
/dev/sdb1: LABEL_FATBOOT="config" LABEL="config" UUID="4AD5-9369" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="config" PARTUUID="8d24a074-ea49-4d24-a17c-82dd88776fa2"

Replace Root Filesystem

Mount Target Device

PC:~$ sudo mount /dev/sdb2 /data2
PC:~$ cd /data2

Replace Root Filesystem

Navigate to the mounted root filesystem, back up the boot directory, delete and replace the root filesystem, then restore the boot directory to the new root filesystem

PC:/data2$ sudo cp -r ./boot ~/
PC:/data2$ sudo rm -rf *
PC:/data2$ sudo cp -av /path/to/rootfs/* ./
PC:/data2$ sudo cp -av ~/boot/* ./boot/

Modify fstab

PC:/data2$ cat ./etc/fstab
### UNCONFIGURED FSTAB FOR BASE SYSTEM

Update the fstab file with the previously recorded UUIDs

PC:/data2$ sudo cat ./etc/fstab
### UNCONFIGURED FSTAB FOR BASE SYSTEM
UUID=8bf96d05-7c97-42fc-863c-95e3e7603ef4       /       ext4    defaults        0       1
UUID=4AD5-9369  /config vfat    defaults,x-systemd.automount    0       2

Unmount

radxa@radxa:/data2$ cd
radxa@radxa:~$ sudo umount /data2

Verify 32-bit Root Filesystem

Boot the System

Insert the SD card or eMMC with the replaced rootfs into the board and power it on.

Verify Current Root Filesystem is 32-bit

radxa@rock-4se:~$ sudo apt-get install file -y
radxa@rock-4se:~$ file /bin/ls
/bin/ls: ELF 32-bit LSB pie executable, ARM, EABI5 version 1 (SYSV), dynamically linked, interpreter /lib/ld-linux-armhf.so.3, Build

This confirms we have successfully replaced the rootfs with a 32-bit version