Table of Contents

Replacing and Reimaging the Nebra Indoor and Outdoor EMMC Key / SD Card

This article provides a step-by-step guide to replace or re-flash the Nebra Indoor and Outdoor EMMC Key/SD Card. Tools required include a Phillips Head Screwdriver/Allen Key Set, Micro SD Card Reader, 64gb A2 micro sd card, and a Micro USB 2.0 Cable. Required software includes Balena Etcher, Balena Raspberry Pi Image, and Raspberry Pi USB Boot. The guide covers the process of acquiring the config.json file from the EMMC Key, flashing the new sd card with the Balena Raspberry Pi CM3 Image, and copying the original config file to the new sd card. This article will be helpful for fixing Helium Miner syncing issues.

Required Tools:

Required software:

Inside the Nebra Helium Miners:

Contents of the Nebra Indoor Miner:

Nebra Indoor Miner

Contents of the Nebra Outdoor Miner:

Nebra Outdoor Miner

  • 1.) 9-16V @ 15W DC 6.5MMx2.0MM Barrel Jack
  • 2.) Ethernet Connector
  • 3.) LED Indicator
  • 4.) Interface Button
  • 5.) 4G / LTE Module Connector
  • 6.) Sim Card Slot

How to replace the SD Card

Step 1: Acquire the config.json file from the EMMC Key:

  • Download and install Raspberry Pi USB Boot, you’ll need this to boot the compute module as a usb file system
  • Identify the and adjust jumper pins on the CM3 daughterboard for programming mode
  • Daughterboard Overview
    • 5.) Micro USB Port used for Imaging
    • 7.) JP4 USB Jumper - Used to switch between normal operation and flash mode, ensure it is in position 1-2 for normal operation and 2-3 for programming.
    • 8.) JP3 Power Jumper - Allows the module to be powered from the Micro USB connector. Only connect when programming from PC and ensure mainboard is not connected.
  • Move the JP4 Jumper to position 2+3
  • Plug in a usb cable and run the Raspberry Pi USB Boot utility
  • Open your file explorer and you’ll see a drive called “resin-boot”. Retrieve the “config.json” file from the directory
  • Unplug the usb cable and reset the JP4 jumper to position 1+2

Step 2: Flash new sd card with the Balena Raspberry Pi CM3 Image:

Step 3: Copy the original config file to the new sd card:

  • Unplug your micro sd card reader and plug it back in after finishing step 2
  • You’ll now see a drive in explorer called “resin-boot”.
  • Copy the config.json file you copied earlier and overwrite the config.json file that is already on the sd card.

Step 4: Install the new sd card and reassemble the Nebra Miner:

  • Install the SD card in the slot in which the EMMC key was previously.
  • Reassemble the miner
  • When first powering the newly flashed Nebra Miner, plug it in with ethernet for 20-30 minutes before setting up wifi connections again.

Step 5: Profit?