Setup 🔗

I am using RM500Q-GL 5G HAT module connected into PI 4 and PI 5. For my conditions I only need LTE signal, because it has better and more stable connection for my use. So I worked with this.

There is difference between setup RNDIS on PI 4 and PI 5. On PI 5 I have Kernel 16.6 and I find some major differences.

• First is that newest Debian using for tethering port eth1 and oldest using usb0.
• Second is, that for newest Debian it's not worked the automatic adding of DNS from Waveshare instruction. So I write my own service, which set it as well.

I have found many conflicts between RNDIS and GNSS. GNSS never worked if the RNDIS start before it. So it's important setup it correctly.

RNDIS 🔗

Before the connection the HAT, you need install following modules

sudo apt-get install minicom

sudo apt-get install udhcpc

Now you can set the HAT.

Setting the Minicom 🔗

1. Open the Minicom:

   sudo minicom -D /dev/ttyUSB2

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2. Check if there is a connection. Command is explained here instruction :

   AT+QENG="servingcell"

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3. Enable the tethering:

   AT+QCFG="usbnet",1

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4. Restart the module:

   AT+CFUN=1,1

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Setting DNS 🔗

Kernel old 🔗

Set DNS by this command

sudo dhclient -v usb0
sudo udhcpc -i usb0
sudo route add -net 0.0.0.0 usb0

Kernel 16.6 🔗

1. Create script for manual DNS config:

   sudo nano /usr/local/bin/hat_autorun.sh

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2. Put this code into the script:

   #!/bin/bash
   /sbin/dhclient -v eth1
   /sbin/udhcpc -i eth1
   /sbin/route add -net 0.0.0.0 eth1

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3. Make the script executable:

   sudo chmod +x /usr/local/bin/hat_autorun.sh

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4. Create the systemd service:

   sudo nano /etc/systemd/system/init-hat.service

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5. Put this code into the service file:

   [Unit]
   Description=Initialize LTE connection
   After=network-online.target
   
   [Service]
   ExecStart=/usr/local/bin/hat_autorun.sh
   RemainAfterExit=true
   
   [Install]
   WantedBy=multi-user.target

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6. Enable the service:

   sudo systemctl daemon-reexec
   sudo systemctl enable init-hat.service

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GNSS 🔗

1. Open the Minicom:

   sudo minicom -D /dev/ttyUSB2

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2. Set automatic turn-on of GPS:

   AT+QGPSCFG="autogps",1

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3. Reboot the module:

   AT+CFUN=1,1

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