01-Linux_Common_System_Customization

Linux System Login Credentials

Ubuntu Username/Password: kickpi/kickpi ROOT Password: root

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Change Default Login User

For Serial Port Login: Modify /lib/systemd/system/serial-getty@.service.d/override.conf

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Enable ROOT Login for Desktop Environment

1. Modify /etc/lightdm/lightdm.conf.d/22-autologin.conf:

[Seat:*]
autologin-user=root  # Change to root
autologin-user-timeout=0
user-session=xfce

1. Modify /etc/lightdm/users.conf:

[UserList]
minimum-uid=0  # Allow UID=0 (root) to log in
hidden-users=nobody nobody4 noaccess
hidden-shells=/bin/false /usr/sbin/nologin /sbin/nologin

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Backup eMMC System to New SD Card (System Backup)

Steps:

1. Insert a high-speed SD card (Class 10 recommended).

2. Format the SD card:

   mkfs.ext4 /dev/mmcblk1

3. Clone the system:

   dd if=/dev/mmcblk0 of=/dev/mmcblk1 bs=4M

   

Notes:

• To disable auto-burn service:

  sudo systemctl disable kickpi.service

• Fix UUID conflicts by modifying /etc/fstab or deleting the file before cloning.

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Backup SD Card System

1. Mount the USB drive:

   sudo mkdir -p /mnt/usb
   sudo mount /dev/sda1 /mnt/usb

2. Run the packaging script:

   sudo ./ff_export_rootfs /mnt/usb/ -t ext4

   Output format: Ubuntu22.04.5LTS_ztl_ext4_202411131114.img

3. Mount the image for modification:

   sudo mkdir test_rootfs/
   sudo mount ./Ubuntu22.04.5LTS_ztl_ext4_202411131114.img ./test_rootfs/

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Set Auto-Start Commands

• Add commands to /etc/rc.local.

• Or create service files in /etc/systemd/system/.

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Configure WiFi Hotspot (AP Mode)

1. Check AP mode support:

   iw list | grep AP

2. Install dependencies:

   sudo apt-get install util-linux hostapd dnsmasq iptables iproute2 haveged

3. Create a virtual interface:

   sudo iw dev wlan0 interface add wlo2 type __ap
   sudo ip link set dev wlo2 address 22:33:44:55:66:00

4. Use create_ap tool:

   git clone https://github.com/oblique/create_ap
   cd create_ap
   sudo make install
   sudo create_ap -c 11 wlo2 wlan0 MyHotspot 88888888

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Connect to WiFi and Obtain IP

1. Configure /etc/wpa_supplicant.conf:

   network={
       ssid="YourWiFiSSID"
       psk="YourPassword"
       key_mgmt=WPA-PSK
   }

2. Connect:

   wpa_supplicant -D nl80211 -i wlan0 -c /etc/wpa_supplicant.conf -B
   dhclient wlan0

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VNC Remote Desktop Login

1. Start VNC server:

   vncserver

2. Modify ~/.vnc/xstartup:

   unset SESSION_MANAGER
   unset DBUS_SESSION_BUS_ADDRESS
   startxfce4 &

3. Restart VNC:

   vncserver -geometry 1920x1080

4. Connect using RealVNC Viewer:

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Install Packages from Ubuntu Repository

Example for installing GCC:

wget http://ports.ubuntu.com/pool/main/g/gcc-9/gcc-9_9.3.0-10ubuntu2_arm64.deb
sudo dpkg -i *.deb

Search for packages at: Ubuntu Packages

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Troubleshooting

Issue: Desktop sound settings crash. Fix:

sudo ln -s pavucontrol pavucontrol-qt

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