Table of Contents
Power Recovery & BIOS Settings
All TetherBoxes are pre-configured to automatically power up after a power cut. If your unit isn't doing this, or you're seeing boot errors, this guide will help you resolve the issue.
Note: This guide applies to the TetherBox Pico, TetherBox Giga, and TetherBox Pro. The entry-level TetherBox (2 and 5 channel) does not have a BIOS.
Symptoms
When BIOS settings are reset, you may experience:
- The unit does not automatically power up when plugging in the power cable
- A "Press F1 to Continue" message appears when connecting a monitor
- Boot errors such as "insert boot media" or "cannot find required map":

- "Reboot and Select proper Boot device" error:

Why Does This Happen?
| Cause | Description |
|---|---|
| Depleted CMOS battery | The CR2032 button battery inside the unit has gone flat and needs replacing. These batteries typically last 3-7 years depending on usage. Extended periods without mains power drain them faster. |
| Power issues | Frequent power cuts or power surges close together can reset the BIOS configuration. |
| Failed system drive | If reconfiguring the BIOS doesn't restore operation, the internal drive may have failed. Contact TetherX to purchase a replacement pre-loaded drive. |
Configuring Automatic Power-Up
Step 1: Enter the BIOS
- Switch your TetherBox off by holding the power button for 5 seconds
- Connect a display and USB keyboard to your TetherBox
- Switch on and immediately start pressing the Del key (or F2 on some models) until you see the BIOS screen

Note: Your BIOS screen may look different depending on the TetherBox generation.
Step 2: Configure Power Recovery
For AMI BIOS (most TetherBox Pico/Giga units):
- Use the arrow keys to navigate to the Chipset tab
- Find Restore AC Power Loss
- Press Enter and select Power On

For Phoenix/Award BIOS (older units):
- Navigate to Main tab
- Find Halt On
- Press Enter and select No Errors

Step 3: Save and Exit
- Press F4 (or navigate to Save & Exit tab)
- Select Save Changes and Reset
- Confirm by selecting Yes

Step 4: Test
- Unplug the power cable from the TetherBox
- Wait 5 seconds
- Plug the power cable back in
- The unit should power up automatically
If the unit does not power up automatically, the CMOS battery likely needs replacing - see below.
Fixing Boot Device Errors
If you see "Reboot and Select proper Boot device" or similar errors, the BIOS may have lost the boot device configuration.
Possible causes:
- Bad connection - Try unplugging and reconnecting the drive cable at both ends
- Failed drive - Contact Support to purchase a replacement pre-loaded drive
- Configuration issue - The BIOS lost the boot device setting (common after CMOS battery depletion or power surges)
Reconfiguring the Boot Device
- Enter the BIOS (press Del or F2 during startup)
- Navigate to the Boot tab

- Select Boot Option #1
- Choose your internal drive from the list (usually shows as the drive model name)

- Go to Save & Exit and select Save Changes and Reset

CMOS Battery Replacement
If the BIOS settings keep resetting after power loss, the CMOS battery needs replacing.
What You Need
- CR2032 button battery - Available from most electronics or watch battery retailers
Locating the Battery
The CMOS battery is a silver coin-cell battery on the motherboard. On TetherBox Pico units (Gigabyte BRIX), it's typically located near the centre of the board:

Note: On some units, the battery may be on the underside of the motherboard.
Replacement Steps
- Power off and unplug the TetherBox
- Remove the case screws and open the unit
- Locate the CR2032 battery
- Carefully remove the old battery (note the orientation - positive side up)
- Insert the new battery in the same orientation
- Reassemble the unit
- Reconfigure the BIOS settings as described above
Tip: CMOS batteries typically last 3-7 years. Units left unpowered for extended periods may drain the battery faster.
Still Having Problems?
If these steps don't resolve your issue, contact TetherX support for assistance.
Related Articles
- TetherBox Troubleshooting - General troubleshooting guide
- Factory Reset - Decommissioning and relocating TetherBoxes
- Remote Power Management - Smart plug integration for automatic power cycling
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