You can build your own Trezor, but here’s the price — DIY wallet engineer

The open-source nature of many hardware cryptocurrency wallets allows anyone to build a do-it-yourself (DIY) wallet like a Trezor from scratch, but it requires certain skills.

Florin Cocos, an electronics design manager from Romania, built his own DIY Trezor with the wallet’s open-source code in 2018 without having access to a “real” Trezor device.

On his YouTube channel, Voltlog, Cocos demonstrated the process of creating the DIY Trezor Model One, using electronics components purchased from distributors like Farnell. The engineer specifically used a Farnell microcontroller and a printed circuit board (PCB) ordered from a production house in China, extracted from a Gerber file available on Trezor’s GitHub.

“The parts can be purchased from any reputable distributor like Farnell, DigiKey, RS, Newark, TME. It really depends on your location; get them from your local distributor. You can get the OLED screen from AliExpress or eBay,” Cocos wrote on his Voltlog blog.

Five years after releasing his DIY Trezor video, Cocos is still enthusiastic about his DIY crypto device. “I have used the device, and I would always trust my DIY device over a marketplace-bought one,” the engineer told Cointelegraph in an interview on Sept. 19.

It took roughly 10 hours for Voltlog to set up the DIY Trezor

Trezor’s market availability wasn’t the main reason for Cocos to build the DIY wallet, though: the engineer was instead focused on spreading the word about open-source projects.

“Open-source designs are gaining more and more popularity, and in my opinion, this is the future,” Cocos said, adding:

“You have full control over the security aspects, and it’s always fun to build something yourself. For me personally, the idea of making something useful, myself, contributes more than anything else to the decision to start such a project.”

The entire process of building and installing firmware on the DIY Trezor wallet took roughly 10 hours for Cocos, minus time spent on receiving the PCBs and other ordered components.

“It took me maybe two or three hours to evaluate the project and generate the necessary Gerber files for uploading to a PCB manufacturing service and ordering all of the required parts from known distributors like Mouser or Digikey,” the design manager said. After receiving the PCBs, it took him roughly five hours to assemble the PCB, flash it with firmware and get it running, Cocos added.

Building hardware for the DIY Trezor was the easiest part, the engineer told Cointelegraph, adding that flashing the firmware and getting it to work with the application was “slightly more challenging.”

How difficult is it to build a DIY Trezor for an average user?

As the whole building process didn’t take too much time, one may think that creating a DIY Trezor might not be that difficult for an average user, but that’s not the case, according to Cocos.

According to the engineer, it’s “nearly impossible” for the average user to build such a device without any knowledge of electronics. “If 10 is the most difficult, then I would rate this a 10,” Cocos said while trying to estimate the difficulty of building a DIY Trezor for an average user.

He added that the process could be simplified, but only at the cost of significant security risks related to supply chain and manufacturing vulnerabilities.

“Things could be improved by creating a ‘makers pack’ for the project, with all of the required manufacturing files in their specific format and just uploading that to one of the PCB and PCBA prototyping services available online. However, while at that stage, it would be a difficulty level of roughly 3 on a scale of 1–10, you lose control over the supply chain and manufacturing step, so there is an added security risk,” the engineer stated.

Cocos suggested that efforts to build a DIY Trezor without proper knowledge could result in significant security risks, adding:

“I would not recommend building such a hardware wallet if you are not experienced with electronics and specifically with soldering small surface mount components. If that’s the case, the result is likely just the magic smoke escaping or, at best, a brick that does nothing.”

Cocos — who described himself as an occasional cryptocurrency user — holds a bachelor’s in electrical engineering and has been designing and building electronics professionally for 10 years and as a hobby for more than 15 years. He believes someone doesn’t need to be an expert like him to build a DIY Trezor, but it still requires some expertise.

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“Just one or two years of tinkering with electronics at a moderately fast pace from a moderately technically skilled person should be enough to greatly increase the chances of success,” Cocos stated.

As previously reported, some cryptocurrency users have fallen victim to fake hardware wallets by buying the devices from sources other than the direct manufacturer or the official vendor. As such, hardware wallet makers like Ledger and Trezor have always urged their customers to buy only hardware wallets from official vendors.

As there are some regions where hardware wallets cannot be shipped due to issues like sanctions, companies like Trezor suggested that the devices’ open-source nature could be a solution. “Trezor is fully open-source; anyone can build their own using the schematics and bill of materials on GitHub,” Trezor’s Bitcoin analyst Josef Tetek told Cointelegraph.

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