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How to Make Your Own Charge-Only USB Cable for the Novatel Mifi

The problem to be solved: You have a lovely Novatel 5410L 4G Hotspot from Verizon, but the battery only lasts 4 hours. If you plug it into a computer’s USB high power port, the device automatically goes into charge only mode, and stops providing any wifi access. The steps below will walk you through how to take an ordinary and inexpensive USB cable and make it work to charge the device via USB and remain a hotspot. You may think you can buy a charge-only USB cable, but it turns out those don’t work with this device – you must short the green/white wires together to trick the device into charging and delivering wifi at the same time. Just having a cable with no green/white data pair does not work. Credit goes to bill-mifi at the Verizon Wireless forums for explaining about the green/white wire shorting idea.

BREAKING NEWS! Verizon put out a firmware update for the Novatel Mifi that actually fixes the problem! Here’s a link to the instructions on the Verizon Wireless website where you can get the firmware update, it’s not the most obvious procedure in the world but it works if you follow them carefully.

If you’re still interested, read on!

Basic steps are, we’re going to cut a USB cable in half, short the green/white wires at the micro-USB side, then reconnect the black/red pair. Solder, Electrical tape and we’re done. I found it helpful to show my work every step of the way to Quality Control Director Steve before proceeding.

But first, let’s watch a short video showing the behavior of the Samsung Mifi 4G with a normal USB cable and then with the modified charge-only USB cable.

Video Demonstrating Why This is Necessary

The video above shows the behavior before and after hacking the cable for the Novatel Mifi. Using a screenreader? Click Here

Buy a Micro USB Cable

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Actually buy several. If you buy from Monoprice.com, they START at $0.65 apiece, if you buy 2+ they’re only $0.62 apiece. I bought 3 because I knew I would wreck at least 1. I was right.

Tools You’ll need

  • Couple of Micro USB cables
  • wire strippers
  • wire cutters
  • box cutter
  • electrical tape
  • scissors
  • soldering iron
  • solder
  • glasses (if you’re over 40)

Tools I Started With

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I prefer the short micro USB cables, here’s how short the ones I suggested are compared ot the mifi. Wire strippers are a must but weren’t as helpful as I thought they’d be.

Cut the Cable in Half

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As you can see from this photo – I cut the cable very close to the micro USB end, which was a big mistake (hence the need for the backup cables). I clipped the wire in with the wire cutters, and then actually had to use the box cutter to cut a ring around the cable before I could use the wire stripper to pull off the outer rubber. I might need a new pair of wire strippers!

When I got past the cable cover, I found first a bunch of shielding wires, then under those I found a thin foil covering as well. I cut all of that back to the edge of the rubber cover.

Closeup of the Shielding

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This is before stripping the inner wires.

Too Short!

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This is where things went wrong – leave yourself PLENTY of length to work with in case you accidentally cut through one of the very thin wires when trying to strip them. Like I did. the wire cutters I have aren’t fine enough, so I was having to use the flat cutter blade they had to just grab and pull and hope for the best.

Short the Green/White Wires Together

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This is the critical step. On the Micro-USB end, twist the green and white wires together. the twist the red to the red and the blakc to the black (basically restablishing the connection. Cut the green and white wires on the big USB end as short as you can so they can’t touch anything.

Test Before Taking Next Steps

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Test the connection by plugging to the high power USB port. On a MacBook Pro this is the port closest to the power adapter.

Odd Error

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I received this error during my first test, but nothing at all went wrong. I didn’t get it again when I had the cable fully stabilized with solder and electrical tape.

Solder

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Solder the shorted green/white wires, and the reconnected black/red wires. I soldered them so they were essentially in line, and in the next step folded them back on themselves. Hope that makes sense…

Tape The Connections

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  • Tape the shorted green/white wires on the micro-USB end.
  • Cut the green/white wires short on the non-micro end.
  • Tape the red wire carefully to ensure no short can happen to the black wire (and vice versa).
  • Trim back all of the foil and insulation wires
  • Test again by plugging into your computer to ensure it charges and broadcasts wifi.

Tape the Whole Thing

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Finally wrap the whole thing as tightly as you can making sure there’s no unprotected areas, and that you’ve taped onto the original rubber coating so it’s stable.

Do a final test and celebrate!