With Krux, it's possible to create a variety of complex puzzles. I personally enjoy designing them, using two Krux devices, combining elements such as encryption, encodings, mnemonics, keys, and passphrases. Now on beta there are account derivations and BIP85 to further enrich the puzzle-making experience.

In the device's user interface, we strive to minimize excessive warnings and avoid blocking features 'for the safety of the user.' However, when communicating with others, I emphasize the importance of caution, backups and tests. Complex puzzles can be bewildering and splitting a wallet's secret into 'x of x' parts can introduce additional risks.
Be careful !

When considering the use of BIP85 child seeds as passphrases, or any other deterministic approach, it's important to be aware that an attacker could potentially brute-force the second secret (the passphrase) from the first secret (the BIP39 mnemonic). As a result, this method introduces a less secure layer compared to adding a non-deterministic secret to your setup.

Yes, we have focused on optimizations to make better use of resources, which also allows us to add new features. Encrypted passphrases could be an interesting addition, but we need to consider if it would introduce too many secrets to manage. We should discuss this further.

There are many other features we plan to add, including one that you also requested: BIP85.

Yes, Jeff, Krux creator, who seemed to be a reserved person, left the project (and all his accounts out there).
Jeff, if you are seeing this, we would love to have you back if you change your mind! Krux changed my life, I'll be always grateful for it! Thank you!

Amigos have a strong white LED flash light in the back, when scanning QR codes you can press ENTER physical button to turn it on. Can be useful to scan paper QR codes in dark environments.
I noticed some of them blink when starting up. It's probably due to a random state of IOs while the device is getting powered up. Sipeed should have used a pull down resistor on the LED transistor driver gate(I checked the schematics and it is missing). Maybe there's a firmware hack to avoid this glitch, but I wouldn't worry about it. The behavior changed on beta14 because now Amigos go to a deeper level o "shutdown".

Another dev, Tadeu created the screensaver. On beta14 I did some optimizations for it to use less resources too. It's useful to grab your attention and don't forget to turn the device off.

Glad you liked the changes!

Power button issues reported above should be solved on version 24.04beta14.
Now after shutdown via menu, to turn it on again, for all devices, it's only necessary to hold power button for 1 second.

Thank you for your feedback! I hope we find a solution for this and we all have a better UX with Amigo!

The manufacturer(Sipeed) does not have a proprietary ecosystem, but a fork of opensource ecosystems (Micropython + OpenMV). OpenMV does have their own hardware, which probably subsidizes the software development, so unless Sipeed donates to openMV it could be considered unfair with OpenMV.

The component we're having issues with is AXP173 PMU, you can find more details about the issue in a post I made here:
https://forum.seeedstudio.com/t/maix-amigo-wake-from-sleep-wont-work-in-some-devices-axp173-pmu/273808

About the Opensats grant:
It is important to mention that, as Krux creator (Jeff) wants, grants won't go to the project. This one will be for me, to support my work on the project on semester 2024/1.
As Krux has more contributors, both OpenSats and me encourage each one to apply individually for grants, if this is something the contributor aims for.
Krux will never ask for donations or manage funds. It won't be an institution neither have a manager.
Having that said, it will help me a lot and I'm excited to retribute to the community.

Amigo's quality:
From what I know, the quality control is not the best, I've seen some issues with camera (most of them fixed with firmware optimizations, next release will have more of them), I've heard of things like a imprecise touchscreen, a screen with 2 burnt pixels rows.
It still amazes me how they can sell a so powerful and featured device so cheap. I have 4 Amigos, the only issue I had with one of them is a weird power manager behavior, but I still believe it may be possible to fix it with firmware. Some components, like the power manager IC, don't have a English datasheet, so it makes it harder to develop proper firmware.

Porting to Other Devices:
I have the goal to port Krux to another device on this semester, it may be an ESP32. But ESP32s are too weak to run video applications. Jade got QR codes signing working with pure C, on a tiny screen. But with Micropython, in larger screens, I would say it is almost impossible to make it work.
An Amigo's competitor like LILYGO® T-Display-S3-Pro costs the same as Amigo, but the MCU has ~half processing power, the screen is smaller, the camera is worse (the same as Amigos's frontal camera).
One possibility to run Krux on cheap and available ESP32s is to make a "blind Krux" version that works with SD cards as the only way to sign PSBTs.
Other port possibilities are OpenMV's Cam H7 and Arduinos Portenta and Nicla Vision. Running with ARM on ST MCUs at 480MHz, these devices are compatible with openMV, which make them very suitable to run Krux. The problem is that, with cameras and displays, these devices will cost 2 or 3 times an Amigo.
There are also other cheap and powerful RISCV devices, like Milk-V and Sipeed's M1sDock but they lack Micropython support and documentation.
Effort will be required to enable cheaper signers. I'll be on it, I know Keith from SeedSigner will be too on his Micropython research.
Soon boards with better chips will be launched, like ESP32 P4 and Amigo's K210 successor, the Kendryte K230. Let's keep improving with them!

Blue sometimes has bugs, where QR codes merge with dark background, other times the QR would get corrupted if you switch to another app then come back.
Some tips that may help:
- Use Blue on light mode (avoid dark mode)
- Use Nunchuk instead of Blue
- Use anti-glare mode on Krux (press down button on the lateral of the device while scanning to activate anti-glare)

Keep is simple is one of our main goals.
The 3 QR codes method you described makes a cheap, quick and easy to use equivalent to a 3:3 multisig.
Sorry about saying the obvious, but is always good to remind, as any x:x multisig if you loose one of the secrets you'll be doomed, please back up them carefully.
Each individual will have his ideal setup, but what freight me the most is to lose the key, so it's a good idea to have redundancies of these secrets.

Thank you Meuserna! Really cool this walk through guide! Loved the photos (without reflections)! This kind of content is really helpful for the project and for people who still don't know Krux and how it can be useful for them!
Thank you JayJuanGee for make it possible the pictures to show up among text!

1: We would have to remove or change some settings (as Testnet) to offer them after a mnemonic is loaded. But yes, just press the reset button and you'll be on "Login" menu with settings after 6 seconds.

2: You do can save encrypted mnemonics on the device as well as SD card, this is optional, and you will find mnemonics you saved even after reboot on "Load Mnemonic->From Storage", and you can access them by typing or scanning the encryption key. You don't need to encrypt/save your mnemonics to use them for sign, you can just load them from external sources and it will be vanished after reboot. Your can delete saved mnemonics on "Tools->Delete Mnemonic". This feature is meant for convenience, and doesn't replace a physical backup.

3: We definitely need a "reset", I think we will first add a "Wipe Device" feature, it will remove all custom settings and saved mnemonics at once.


IPS x TFT
Some Amigos ship with different displays, which use mirrored X coordinates. Most Amigos have TFT, but if you flash it and notice things are in mirrored places (ex on keypad letter "a" is on the right and letters increase towards left) then you have a IPS screen and should re-flash your amigo with IPS version.

Mac version
We have a lot of issues when flashing from Mac devices, so we offered two options for mac users, one built over OS version 10 other for version 11. Fortunately you didn't seem to have issues.

Really heart warming to see your appreciation of our work on Krux!
About the app, it's very easy to install, just download the and install .apk file (and work around Android complains about not being known source)
Here's the link: https://github.com/odudex/krux_binaries/tree/main/Android
As the app intro screen says, it is intended for learning purposes.

Krux uses standard AES encryption methods, a brief explanation of encrypted QR codes can be found here:
https://github.com/odudex/krux/blob/develop_rc/docs/encrypted-qr-codes.en.md
The encryption for flash and SD card uses the same methods, but the data is available in json text format, so is even easier to know what to do to decrypt.
I have plans to do a simple python script to encrypt/decrypt krux mnemonics from json files and QR codes without the device(it would be very simple and straight forward). The Android app is also a good emergency item to have, specially for encrypted mnemonic QR codes, as they are interoperable between all devices.
It's a new and unique feature, and produces one more key to manage, so must be used with care.

Krux is currently going through a change right now, I'm updating the official repository(selfcustody) with all the features you see in beta, from my repository(odudex), and a new official release is about to be done. But if you're going to do a review please consult the updated documentation from here for now:
https://odudex.github.io/krux/getting-started/

Soon everything will be available on official repository:
https://selfcustody.github.io/krux/getting-started/

The feeling you described about Krux is the same I felt ever since I knew it. The hardware is very well suited for the application, the project architecture and structure were very well thought by Krux's creator, Jeff, and it has a lot of potential to improve.

Thanks(in the name of all Krux contributors)! I encourage you to build them, but I warn you it is addictive, once you build one you'll want all types
Regarding the law, the way I see it is there's one great thing about Krux: There's no business! No consumers or clients to "be protected". We are just a few nerds having fun with code e general purpose hardware at our own risk. No one asked for trust or money, all we want are scrutiny and ideas to improve our toys

Sorry to hear that, I believe we won't be able to go lower than Android 6.0. But the effort to lower the requirements was fruitful. Thanks for testing!

You may try the last version. It is now compatible with armv7 chips (not only v8). I tested on a Android v6.0, it wasn't working, now it is!

Yes, the buttons and small screen don't make a good UX, but as M5stickV was the first Krux device and has its fans for being so tiny it will always get our attention and updates.
Amigo UX, on the other hand, is really smooth, and still has a lot of room for improvements.

I'll see if I find some older phone to check if its possible to build the app for them too.

Even M5stickV has 3 buttons now. After an update, power button can be used to navigate(go back).
DIY version Dock navigates using a rotary encoder.

-Android:
I don't know how old Androids will handle the app. As the app doesn't require anything fancy I hope it has some wide range of compatibility. I have some cheap, but not old phones to test. If you try let us know if it worked.
- Linux, Windows, Mac
If you have a PC running python, on any OS, by installing some requirements you can also run a very functional simulator from source code. It's a very good to start point to play with Krux code.

Krux smaller devices has 3 buttons, and the most popular, Amigo, has capacitive touch screen. You could check the Android app to have an idea of what we are talking about.

That's what passphrases are for. You can also write your seed in different ways, formats, number bases, encodings, encrypted, but sure this is not for everyone. Most people should just trust companies and go with mainstream solutions.
Krux has a supporting role in sovereign strategy, it's a Swiss army knife for create and load seeds in a variety of forms and to sign PSBTs and messages, it requiring less trust.

Yes!