qmk_firmware VS qmk_toolbox

I do wonder how much of that can be accounted directly to the RP2040. Projects like QMK[0] have been using a technically quite similar codebase for making DIY keyboards for quite a while now.

At first glance I'm not really seeing anything in GP2040 which couldn't have been done with any other somewhat-modern MCU. The RP2040 has undoubtedly been the catalyst leading to GP2040's widespread adoption, but it seems the same could've happened with a Pro Micro instead.

[0]: https://github.com/qmk/qmk_firmware

I definitely think you should be able to add keyboard layouts at a software level on iPadOS and iOS, but one possible solution to the problem right now is using a programmable keyboard using QMK [1], ZMK [2], or some other open-source firmware. There's even a usb-usb converter [3] that will convert keystrokes from any keyboard into ones that you map using TMK or QMK, so you can use your own.

[1] https://qmk.fm/

[2] https://zmk.dev/

[3] https://geekhack.org/index.php?topic=69169.0

I only use keyboards running QMK or ZMK, so:

My Caps Lock key is a Control/Escape key (when tapped it behave like a Escape, when hold it's Control), and my left Control is a one shot layer switch key [1], which means I tap LCtrl once, and then press Caps Lock + 5 to get Ctrl+F5. Doable with single hand and more ergonomic as I have an unusually small hand.

[1] https://github.com/qmk/qmk_firmware/blob/master/docs/one_sho...

I agree that reduced finger movement is a crucial step in achieving typing efficiency. This is nicely solved by mod tap modifiers in QMK/ZMK[1] where key acts as a char when tapped and as a layer while pressed.

[1]: https://github.com/qmk/qmk_firmware/blob/master/docs/mod_tap...

Separate wireless controller, see the glue code at [0]

[0]: https://github.com/qmk/qmk_firmware/compare/master...nuphy-s...

If you have a keyboard that runs QMK firmware[0] with the VIA[1] feature enabled[2], then there is a convenient testing app available from the same place you customize your keys [3].

[0] https://qmk.fm/

I made a layout that I'm happy with. Spanish is my native language, so it has characters like the accents and 'ñ', but it's meant to be used for programming as well. Visual Studio uses a lot of Ctrl and Ctrl + Shift shortcuts, so I left them in the same place as the default Corne layout so I can press them both with my pinkie finger. Perhaps some of the ideas are useful to you.

Also, it would be possible to do this for the RP2040. However, it needs some work to get working. but for example: https://github.com/qmk/qmk_firmware/pull/20999

Flashing custom firmware - the current version QMK tool off the website won't work. You'll most likely get a "USB device connected (NO DRIVER): WB Device in DFU Mode " and not be able to flash anything. You will need the beta version that supports WB32 flashing utility. I grabbed mine from the GMMK guide QMK tool from GMMK

You first have to download QMK toolbox https://github.com/qmk/qmk_toolbox/releases/download/0.2.2/qmk_toolbox.exe. Once downloaded, download this bin file https://github.com/GHv4/Sense75-CAPSLOCK-UNDERGLOW/blob/main/sense75-CAPSLOCK%20UNDERGLOW.bin. Open the QMK toolbox exe file, then hit the open button. Locate the .bin file. Hold Right FN+BACKSPACE until it pops up in QMK Toolbox. Hit flash and wait for it to finish flashing. Via and Vial compatible. YOU'RE WELCOME FRIENDS!!

Flash it with qmk toolbox: https://github.com/qmk/qmk_toolbox/releases

I got things working by using the https://github.com/qmk/qmk_toolbox project, and the firmware file you linked. As you said, my pad now works with Vial, and has 12 layers. Though the layer selector still only traverses between layers 0 through 3.

- QMK MSYS: you'll need it for many things, for compiling your firmware file and for flashing, especially if flashing with QMK Toolbox isn't permitted in firmware settings (in this case QMK Toolbox just won't recognize your keyboard);

I am currently using the QMK online configurator tool to do the compilation and download the resulting .bin file, and then the QMK Toolbox to flash it onto the keyboard.

Check out this site: http://kpchn.com/s/PoHJ. I found it from the AliExpress page and it leads to all the VIA/VIAL configs for the KPRepublic boards. Go into CSTC75 and you'll see a .hex file, that's the firmware. You should be able to use the QMK toolbox: https://github.com/qmk/qmk_toolbox to flash the firmware.

Tool needed to flash your keyboard (QMK Toolbox) can be downloaded here: https://github.com/qmk/qmk_toolbox/releases/tag/0.2.2

When I first plugged them in, my Mac (running 13.1 Ventura) recognized them as a USB storage device. I was trying to use the QMK toolbox to flash the firmware onto them, not realizing that I needed to drag and drop a .uf2 file instead of trying to flash a .hex file.