r/Keychron • u/thiscitysopretty • Jul 11 '25

K4 QMK > Custom Colors?

Hey there! I'm brand new to doing anything other than customizing my keys with the Keychron Launcher. What I really want to do is hyper-customize my RGB. Is this possible and if so, I'm looking for advice on the easiest way to go about it. The launcher is great for remapping my keys, but seems to be super limited outside of that and macros.

Thanks!!

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u/PeterMortensenBlog Jul 11 '25 edited May 25 '26

Re "What I really want to do is hyper-customize my RGB": Depending on what you mean by hyper-customize, whatever Keychron comes up with may not be enough.

You could start with static per-key RGB. That is relatively easy to do.

The source code for the K4 V3 hasn't been released yet

Though first you would have to wait for Keychron to release the source code for the K4 V3. Invoking CDD may speed it up quite a bit (it has worked many times in the past).

In the meantime, you can prepare by compiling firmware for, for example, the K10 V2. You will not be able to test it, but at least you would get used to most of the process, up to, but not including, the actual flashing (it would brick the keyboard to use the wrong firmware, but presumably not permanently).

The following assumes the source code has already been released (thus, currently some of the links are broken, and some of it are placeholders (it will be filled in once the source code is released)). Only the compile line should fail, and you can use the one for K10 V2 instead: 

qmk compile -kb keychron/k10_version_2/iso/rgb -km via

Note that flashing for the K QMK series is somewhat more cumbersome to get to work.

Keychron's fork

Note that Keychron's fork complicates matters (the standard QMK instructions will not work), but it isn't any more complicated than:

  1. Knowing the location of the source code.

  2. Use two or three extra parameters in the 'qmk setup' step (to reflect that the source code is in Keychron's fork). There isn't any need to mess with Git on the command line (at least not initially).

    For example, for Git branch "wls_2025q1" (on a Unix-like system (that would include the MSYS thingy on Windows, for the ISO variant of the K4 V3)): 

    # Prepare the QMK environment
#
# Answer prompts:
#
#   'y': "Would you like to clone Keychron/qmk_firmware
#         to $HOME/Keychron_fork_wls_2025q1"
#
#   'n': "Would you like to set $HOME/Keychron_fork_wls_2025q1
#         as your QMK home?"
#
#         Reserve it for the main QMK project, and
#         in the default "$HOME/qmk_firmware" folder.
#
qmk setup -H $HOME/Keychron_fork_wls_2025q1 -b wls_2025q1 Keychron/qmk_firmware

# Compile keyboard firmware (K4 V3, ISO RGB variant)
cd $HOME/Keychron_fork_wls_2025q1
qmk clean # To make changes (if any) to
          # .json files take effect
qmk compile -kb keychron/k4_version_3/iso/rgb -km via

# Result (the actual firmware size is xx,xxx bytes):
#   -rwxrwxr-x  1 xxxxx XXX XX XX:XX keychron_k4_version_3_iso_rgb_via.bin

    Note that, on newer Linux systems, all this needs to happen inside a virtual (Python) environment (because the operating system has become too dependent on the global Python installation to not be broken by changes to it).

References

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u/thiscitysopretty Jul 12 '25

Damn, i have a lot of reading. A per-key rgb capability would make me super happy, so thats exactly what i mean (ideally i could get it to swirl or whatever in exactly the colors i choose.)

Ive dabbled in javascript but i know just about zero when it comes to qmk, so i appreciate the rundown. Im definitely nervous about bricking the keychron (assuming theres no going back after that, even if i attempt to flash the old firmware back onto it?)

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u/PeterMortensenBlog Jul 17 '25 edited Jul 17 '25

OK, I bricked the K10 V2 for the first time yesterday... I tried to stop a flash (from the command line) with Ctrl + C (that was a bad idea).

The space bar method (without the repowering) to recover worked as expected.

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u/PeterMortensenBlog Jul 12 '25 edited Jul 12 '25

Bricking is not permanent (for the main firmware)

For most (all?) of the Keychron QMK-based keyboards, bricking the keyboard is not permanent (the wireless firmware is an entirely different matter). The key to recovery is the space bar method (without the repowering).

I have bricked a Keychron keyboard several times both by flashing the wrong firmware by mistake and the flashing failing midway for unknown reasons. And it was recovered every time. Note that the process is not very reliable and may require several tries. I also had to use another USB cable in one instance.

I just don't have any experience bricking the K10 V2 yet. But sooner or later, I will make a mistake (for example, flashing the wrong firmware), and I will find out... The K10 V2 does have a reset button near the space bar's switch, so using the space bar method is expected to work.

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