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FAQs for reTerminal Usage

This document contains all the frequently asked questions related to reTerminal. This will be very helpful if you are suffering from any issues when using the reTerminal.

Q1: How can I flash Raspberry Pi OS which is originally shipped with reTerminal?

If you have flashed to a different OS and want to switch back to the default Raspberry Pi OS which is shipped with reTerminal, you can follow the steps below

Note: reTerminal is originally shipped with 32-bit OS. However, you can download a 64-bit version as well

  • Step 2. Extract the .zip file

  • Step 3. Open Raspberry Pi Imager software

pir

  • Step 4. Press CTRL + SHIFT + X on the keyboard to open Advanced options window

pir

Here you can set a hostname, enable SSH, set a password, configure wifi, set locale settings and more

  • Step 5. Click CHOOSE OS and select Use custom

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  • Step 6. Navigate to the previously extracted image, select it and click open

  • Step 7. Click CHOOSE STORAGE and select the connected eMMC drive

  • Step 8. Finally, click WRITE

Q2: How to upgrade Raspberry Pi OS and the installed packages

We will update all the packages and also the Raspberry Pi OS to the latest version

  • Step 1. Open a terminal window on the reTerminal and type the following
sudo apt update
sudo apt full-upgrade
  • Step 2. Reinstall kernel headers
sudo apt install raspberrypi-kernel-headers
  • Step 3. Reboot the reTerminal
sudo reboot

Now your Raspberry Pi OS and all the necessary packages are up to update!

Q3: How can I flash OS if I replace the CM4 with non-eMMC version

If you want to use a Compute Module 4 without eMMC on the reTerminal, then you need to insert a micro-SD and flash the OS of your choice. Follow the steps below according to your operating system.

  • Step 1. Insert a micro-SD card to the computer using a micro-SD card reader connected to the computer, or by using a built-in card reader on a laptop

  • Step 2. Download Raspberry Pi Imager software by visiting this link

Note: You can choose to download for either Windows, Mac or Ubuntu

  • Step 3. Open Raspberry Pi Imager software

pir

  • Step 4. Press CTRL + SHIFT + X on the keyboard to open Advanced options window

pir

Here you can set a hostname, enable SSH, set a password, configure wifi, set locale settings and more

  • Step 5. Click CHOOSE OS and select your preferred OS

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NOTE: You can select OS such as 64-bit Ubuntu by navigating into Other general purpose OS

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  • Step 6. Click CHOOSE STORAGE and select the connected micro-sd card

  • Step 7. Finally, click WRITE

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Please wait a few minutes until the flashing process is complete.

  • Step 8. Eject the micro-SD card from computer and insert it into the reTerminal.

pir

Note: You need to open the shell of the reTerminal to access the micro-sd card slot

Q4: How can I log in to Raspberry Pi OS/ Ubuntu OS or other OS using a USB to serial converter

If you have a USB to Serial Converter, you can use the following steps to log in to Raspberry Pi OS

Connect jumper wires from a USB to Serial Converter to the UART pins on the 40-pin GPIO header of the reTerminal as follows

pir

Now let's configure the software on the computer. Please follow according to your operating system

For Windows

  • Step 1. Connect the USB to Serial Converter to the PC

  • Step 2. Open Device Manager by typing Device Manager in the windows search box

  • Step 3. Click on the drop-down arrow from Ports (COM & LPT) and find the name of the connected serial port (ex: COM7)

pir

  • Step 4. Download and install Putty by visiting this link

Note: Putty is an SSH and telnet client where you can use it to connect to the reTerminal via SSH. You can skip this step if you already have Putty installed

  • Step 5. Open Putty to connect the PC to the reTerminal

  • Step 6. Select Serial under the Connection Type

  • Step 7. Configure the settings as follows:

    • Serial line: COM7 (choose your COM port)
    • Speed: 9600

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  • Step 8. Click Open

  • Step 9. On the Putty window, enter the login details as follows

- Username: pi
- Password: raspberry
  • Step 10. If you have sucessfully logged into the Raspberry Pi OS, you will see the following output

pir

For Mac/Linux

  • Step 1. Connect the USB to Serial Converter to the PC

  • Step 2. Open a terminal window on Mac/Linux

  • Step 3. Type the following to update the packages list

sudo apt-get update
  • Step 4. Type the following to install minicom
sudo apt-get install minicom
  • Step 5. Type the following in the terminal to view the connected serial devices
dmesg | grep tty

Ex:
[ 1562.048241] cdc_acm 1-3:1.0: ttyACM0: USB ACM device

  • Step 6. Connect to the serial device by typing the following
minicom -D /dev/ttyACM0 -b 9600

Note: The baud rate is set to 9600

  • Step 7. After the hardware connections mentioned above, turn on the power from the wall power socket to power on the reTerminal

Now you have successfully logged into Raspberry Pi OS.

Q5: I cannot wake up the reTerminal LCD after sleep

Open a terminal window after connecting through SSH or VNC and enter the following commands

DISPLAY=:0 xset dpms force off
DISPLAY=:0 xset dpms force on

This will reinitialize the LCD on the reTerminal

Q6: How can I boot an OS from USB Flash Drive

You can boot an OS from USB Flash Drive by following the steps below. Here we change the boot order to USB Boot > eMMC Boot, which means, if the USB Boot fails, it will boot from eMMC.

Note: You will have to use Ubuntu or MacOS as host PC for this method.

  • Step 1. Remove the 4 rubber covers and open the reTerminal back shell unscrewing the 4 screws underneath

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  • Step 2. Remove the 2 screws to disassemble the heatsink and also the remaining 4 screws to take apart the entire case

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  • Step 3. Flip down the boot mode switch according to the below diagram

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  • Step 4. Open a Terminal window inside the Host PC after connecting to reTerminal and type the following to update the packages list
sudo apt update
  • Step 5. Install Git by the following command
sudo apt install git
  • Step 6. Git might produce an error if the date is not set properly. Type the following to correct this
sudo date MMDDhhmm

NOTE: Where MM is the month, DD is the date, and hh and mm are hours and minutes respectively.

  • Step 7. Clone and enter the usbboot tool repository
git clone --depth=1 https://github.com/raspberrypi/usbboot
cd usbboot
  • Step 8. Enter the following to install libusb
sudo apt install libusb-1.0-0-dev
  • Step 9. Build and install the usbboot tool
make
  • Step 10. Open the bootloader configuration file
sudo nano recovery/boot.conf
  • Step 11. Change the BOOT_ORDER field to the following
BOOT_ORDER=0xf15

Note: Here if USB Boot fails, it switches to eMMC boot

  • Step 12. Run the following to update the EEPROM image
cd recovery
./update-pieeprom.sh

The pieeprom.bin file is now ready to be flashed to the Compute Module 4

  • Step 13. Navigate back to the usbboot directory
cd ..
  • Step 14. Run the usbboot tool to flash the bootloader EEPROM
sudo ./rpiboot -d recovery
  • Step 15. Connect reTerminal to the PC via USB Type-C cable

Now it will take a few seconds to transfer the necessary files to the reTerminal.

  • Step 16. Turn off reTerminal, flip the Boot Mode switch back to the original position and assemble the reTerminal shell

  • Step 17. Connect a bootable USB Flash Drive with a suitable OS inside, connect to one of the USB Ports on the reTerminal and turn on reTerminal

Now you will see reTerminal booting from the connected USB Drive

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