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Using U-Boot to debrick your KVM

If you bricked your KVM due to some DIY projects or flashing a wrong firmware, your KVM may not be able to power up properly. In this case, you can re-install the firmware by using U-Boot failsafe.

Preparation

Please prepare a computer with an Ethernet port.

If your computer does not have Ethernet port, prepare an additional USB Ethernet Adapter.

Debrick steps

  1. Please download firmware here to your computer.

  2. Remove the power of KVM. Connect your computer to the Ethernet port of the KVM.

  3. Press and hold the Reset button firmly, at the same time power up the KVM.

    Then you will see the LED flashing in a regular sequence a few times—please release your finger after the sequence changes.

    • For Comet (GL-RM1), the blue LED light flashes 5 times, then release the Reset button, the blue light will stay on.

  4. Manually set the IP address of your computer to 192.168.1.2. Please check the step-by-step guide for different operating systems below.

    Windows 7 / Windows 10

    1. Go to Control Panel -> Network and Internet -> Network and Sharing Center -> Change adapter settings.

    2. Right click Local Area Connection -> Properties.

    3. Click Internet Protocol Version 4 (TCP/IPv4) -> Properties.

    4. Set the IP adress to 192.168.1.2 manually.

    5. Set the Subnet mask to 255.255.255.0.

      ipv4 properties

    6. Click the OK button.

    Windows 11

    1. Open Settings.

    2. Click on Network & Internet.

    3. Click the Ethernet tab.

      windows 11 ethernet

    4. Under the "IP assignment" section, click the Edit button.

      windows 11 ethernet edit

    5. Select the Manual option.

      windows 11 ethernet edit

    6. Turn on the IPv4 toggle switch.

    7. Set the static IP address as 192.168.1.2.

      windows 11 ethernet edit

    8. Specify the Subnet mask as 255.255.255.0.

    9. Click the Save button.

    macOS

    1. Click the Apple icon in the top left corner of the screen, and select System Preferences.

      macos system preferences

    2. Click Network.

      macos system preferences network

    3. Click Ethernet on the left and then click the drop-down box next to Configure IPv4 and select Manually. If you are using a USB Ethernet Adapter, Ethernet may not be found and it may show up as the name of the USB Ethernet Adapter.

      macos ip manually

    4. Enter the IPv4 Address to 192.168.1.2, Subnet Mask to 255.255.255.0, Router to 192.168.1.1, then click the Apply button in the lower right corner.

      macos ip manually

  5. Use browser to visit http://192.168.1.1. This is the U-Boot Web UI.

    Uboot web ui

    Note: The U-Boot Web UI above may not be exactly the same as what you see, because the U-Boot version is different for different production dates. For security reasons, we currently do not provide separate U-Boot upgrades. If an update is necessary, we will integrate it into the new firmware.

  6. Click Choose file button to find the firmware file. Then click Update firmware button.

  7. Wait for about 3 minutes. Do NOT power off your KVM when updating.

    The KVM is ready when its LED is flashing white.

  8. Revert the computer IP setting you did in step 4.

  9. Unplug the Ethernet cable between your computer and the KVM, then connect your KVM to a network source (e.g. a router or a network switch) via this Ethernet cable. For Comet Pro (GL-RM10), you can also connect it to the Wi-Fi.

    Wait for about 1 minute to allow the KVM to obtain Internet access. Then connect your computer to the network source, and you will be able to access the KVM via glkvm.local again.

    Note: Configuration settings are typically retained. However, they will be reverted to default if a configuration error caused the system failure that required recovery.

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