Corne V3

A build log and brief review of the Corne V3, as well as the Kunai case.

Corne V3

I was never a big fan of ergonomic keyboards, mainly because I never truly liked the aesthetics and acoustics of even the more premium variants, like the Moonlander for example. I’m so deep into the Happy Hacking layout, that I never really felt like making an effort to try something else. However, if you happened to stumble upon my previous updates post, you might remember that I’m working to simplify my equipment, especially those items that I’m looking forward to bringing with me on my travels. A dedicated keyboard is one of these items, given the mediocre keyboard of my – and pretty much anylaptop. With a big trip coming up, I decided that it was the perfect time to take on building a portable and lightweight alternative to my everyday keyboard, and an ergo board appears to be as compact as it can get.

Back in 2021 one particular release in the ergo spectrum got me very interested: The Angry Mio Hatsu. I instantly fell in love with the design language of the Hatsu split keyboard. However, with a price tag of USD 1600, this particular mechanical keyboard was well beyond what I was willing to spend. Besides, after researching the Hatsu in depth, I found it to be relatively clunky and filled with components that I wouldn’t need: A 5000mAh Lithium battery, Qi wireless charging, Bluetooth; I prefer cables.

Fast-forward one year and I stumbled upon a post, by someone who goes by the nickname mell0w, that immediately caught my attention. The person designed an interpretation of the AM Hatsu, for the wildly popular Corne, by foostan. The case resembles a similar design language, yet is adapted to fit the flat and more minimalist shape of the Corne. mell0w went ahead and posted the full specs:

  • Corne v3
  • Keyhive Acrylic Plates
  • L+F Kiwi housing+Purple Panda stems, 78g Sprit Slow Extreme IIs
  • Kunai case
  • BowJian Smoke Black keycaps

Not only that, but they also uploaded the STLs for anyone to give it a go. I knew I had to try it eventually.

Let’s do this!

One year later...

Okay, I had 67 days left until my next trip would begin and I wanted this keyboard to be my travel keyboard. I had to make sure things went as smoothly as possible. While you might think that 60 days is plenty of time to build something as simple as the Corne, there’s always potential for delays. Just imagine ordering the board online and receiving the wrong board. And imagine the replacement for that wrongly delivered board being delayed or maybe even never arriving. But that would never happen, right?

I ordered the Corne V3 Cherry MX from Boardsource on February 10th. Boardsource shipped the package two days later, on February 12th and I received it on February 20th.

With the Corne V3 in my hands, I went straight to work, crammed out my SainSmart TS80P soldering iron, and started building the ergo board according to the documentation provided by Boardsource.


Soldering the diodes and LEDs was a bit of Yak-shaving, but everything went well until I reached the chapter Switch Sockets in the manual. I was starting to doubt myself because I simply couldn’t get the sockets to align with the holes in the PCB. This was when I checked the other side of the PCB and saw that it said Corne Chocolate v3.0 by Boardsource.

“Chocolate?”. I looked back at the MX sockets in my hand, and back again at the PCB. “Chocolate…”.

I immediately checked the order from Boardsource and couldn’t find any indication that I would have ordered the wrong PCB or the wrong switch sockets. Something seemed to have gotten mixed up, though. In my left hand, I was holding a PCB that was designed for the so-called Choc low-profile switches by kailh. In my right hand, I was holding a regular MX-style switch socket. Clearly, these two won’t go together. As I did not have any low-profile equipment available whatsoever, I had to pause the build and get in touch with Boardsource. 57 days left.


The Boardsource experience

I wrote Boardsource on February 21st to let them know that my order got messed up. As I didn’t hear back from them in the following days, I wrote a second e-mail, on February 26th, to a different e-mail address, to which their support replied shortly after.

After clarifying the issue, Boardsource offered to send me the correct PCB, including all the parts that I had already soldered onto the Choc PCB. “Awesome!”, I was thinking. Boardsource sent an e-mail and asked for me to confirm the previously used delivery address – which I did – so they could ship the package. I put away the halfway-built keyboard, as I didn’t have Choc sockets, switches, or keycaps to continue, and decided to wait for the correct package to arrive.

On February 29th I received the USPS tracking number from Boardsource. I kept checking the status occasionally when, on March 5th, the USPS site said Addressee Unknown: Return to Sender.

“Wait, what?”, I was puzzled and contacted Boardsource, informing them about the situation and asking them to double-check the address. Ideally they could contact their carrier to request a re-delivery. There was no reason for the same address to be unknown all of a sudden. 43 days left.

Boardsource replied to me with a copy of the postage label and the info that they cannot request a re-delivery and, if I wanted to, they could ship it again, but I’d have to pay the delivery cost. When I opened the PDF with the label, I saw that the address was wrong though. Boardsource asked me to confirm the address, which I did, but they went ahead and sent the package to a completely different, non-existent address. And even when they forwarded me the e-mail containing the label, they didn’t seem to notice that the address was wrong. I went back to my HHKB and typed ahead, informing Boardsource about the address issue and quoting the previous e-mails in which I explicitly confirmed the correct address. Moments later Boardsource replied, requesting me to confirm my correct address again, which I did one more time, at which point they replied that they would look into the issue.

Is it me?

At that point I got curious: Is my order jinxed or is it maybe the folks at Boardsource that might have had a little too much solder fumes and PBT vapor lately? I began searching online for other people’s experience with Boardsource and it didn’t take long to find something:

The first order - full kit … There was one big problem after assembling it though. One key didn’t register keypresses :| …

Second order - a pack of switches … I ordered 40 switches and got 38. Oh well, shit happens. …


… I did some continuity testing and discovered that the trace that lead from the COL3 terminal to the switch terminals was broken somewhere near the start. …

… I had an issue with my order where several months went by and and I never got a shipping notice … Unfortunately, when I got my order, it was clear that the oled covers were not new. It looked as though they were scraped with sandpaper. …


It appeared as if Boardsource lacked a pair of eyes that could have a last look before shipping things. Short story long, I had to wait for USPS to ship the wrongly labeled package back to Boardsource before they would re-ship it again. On March 13th Boardsource confirmed retrieving the package:

Hello, we got your package back today!

I will re-ship it today, here is your new tracking number: 9234XXXXXXXXXXXXXXXXXXXXXX

Please send $10 to ‘’ on PayPal.

Thank you very much for your order and support, we appreciate you as a customer. Please reach out to us if you need further assistance.

The request to send $10 to a PayPal address was puzzling, as I thought that this had been clarified. If they had informed me that they wouldn’t send the package another time without payment, even though the failed attempt was their fault, we could have figured something else out, e.g. a discount on the wrong item that I received, that would allow me to get the required hardware to finish the board, even though it wasn’t what I had ordered. With only 35 days left, time was running out.

I replied to that e-mail, asking for clarification, and received a reply a day later, informing me that it was due to my forwarder who “likely refused the package for an unknown reason” – which wasn’t true. The package never reached my forwarder.

At that point I got frustrated, losing hope that I would ever receive the MX board I had initially ordered. This whole situation had been going on for 33 days and it didn’t appear to come to an end. As it didn’t make sense to me to continue the back and forth I formulated what I thought was one last reply to Boardsource, in which I reiterated the whole situation, trying to make it clear that it was them who initially sent the wrong item, and that it was also them who sent the package presumably containing the correct item to a wrong address, and that now they are charging me extra for a third attempt. I accepted the fact that I would never get the MX board from Boardsource and I told them that I’m not going to pursue this topic any further. I would either have to scrap the project – and this post! – or invest another Benjamin to get the missing pieces.

It was sad how the situation had turned out, especially after waiting an additional three weeks for nothing. I spared explaining to Boardsource the details of wanting to build this project for an upcoming trip, and that I had already spent money on a 3D-printed case. At this point, I was willing to let go.

Ah, right, the 3D print!

Meanwhile, I had the case printed by someone living on the other side of the city. It had cost me $75 – which was about the same price I got quoted on Hubs Protolabs for identical specs. However, I thought that rather than ordering a 3D print online and having it shipped thousands of miles, I could support a local business and probably get it quicker, at a similar level of quality. I came to regret this decision. Communication was surprisingly hard and not only did it take nearly a week to schedule the pick-up of the part, the final result was well below the standard that I’m used to from Hubs Protolabs:

In certain parts of the print it was obvious that something bad happened to the nozzle. I don’t know whether the printer malfunctioned, or the person in charge rushed the print too much, or they were simply not experienced enough to print slightly more complex parts like these, but ultimately I knew that I’d have to get a few tools and put in some proper work to even out the imperfections. This was something that I certainly wouldn’t be able to do within the set timeline unfortunately.

The Boardsource experience continues

Eventually I received the following reply from Boardsource:

Hi Marius,

I am sorry if things got messed up in terms of shipments/labels. You do not need to worry about the additional shipping label cost, I truly thought the re-shipment was in reference to the original order, and the original order and re-shipment have the same address.

It is somewhat common for shipping forwarders to send a package back to us if the forwarder is not made aware that they are receiving it (some forwarders require they are made aware of an incoming shipment) and when that happens the post office codes it as as an improper address.

It is our policy to cover costs on re-shipments when the problem is our fault or due to a system error. However, we do charge for re-shipments when the package is returned to us due to customer error or non-payment of customs/import fees.

I got very mixed up in terms of the timeline of this order and what happened or what went wrong. I am still not sure why a replacement went to the wrong address or why the shipping provider didn’t accurately represent the address on the replacement.

I assure you I am not trying to get an extra $10 if the fault was ours. We are in the middle of transitioning to a new Customer Service suite and also training an new individual to handle Customer Service inquiries. As a result some of the context of your email thread was not present, and due to the characters in your email I am unable to respond within the system and some our replies were marked as ‘undeliverable’ in the email system. I know it’s a series of unfortunate events and I also understand how this is frustrating for you.

We have a very good reputation for expedient customer service and helping customers however we can, I am really sorry you didn’t get the normal Boardsource shopping experience.

At this point, I would like to just offer a full refund on the order(s) and you can order whatever you want from a different source that may work better for you. There is no need to send back any item(s) you have from us.

I have issued a full refund for Order 1546 ($107), if there are outstanding costs you incurred as a result of doing business with us I am happy to manually send those funds to you via PayPal or another service (like shipping forwarding costs, etc.).

Really sorry this one didn’t work out as intended!

My first thought was: Hah, another system that does not support Punycode domains! On a more serious note, though, I appreciate the time Boardsource took to openly explain what was going on behind the curtains, and that they eventually got a clear picture of what had happened with my deliveries. I also appreciated the gesture to refund the purchase in full, but it didn’t sit right with me.

The main source of my frustration was the fact that Boardsource attempted to charge me another $10 for re-shipping the package, even though the errors happened on their end. All I wanted was to get what I initially ordered. Letting me keep the Choc board for the sake of not incurring more shipping fees was already a nice gesture that I appreciated, but not paying anything for it at all didn’t feel right – even if it wasn’t what I had ordered in the first place.

After the refund hit my credit card I got back to Boardsource:

Hey there Quinn,

Thank you kindly for explaining the situation and refunding me the purchase. Even though I didn’t receive what I had ordered, I did receive something, hence I don’t feel it would be the right thing to accept the full refund.

I have ordered a $50 gift card from Boardsource and destroyed the gift card code I just received by mail so that it won’t be redeemed. Please do not attempt to send a physical gift card by mail.

I truly hope this experience with Boardsource is indeed the exception to the rule, and future customers get to enjoy the normal shopping experience!

Best regards,

When life gives you onions, make onionade

Even though this project already began slightly disappointing, with a 3D print that wasn’t exactly on par with previous prints, and even though it took an even sharper left turn with the Boardsource delivery situation becoming FUBAR, I nevertheless decided to go ahead and at least try to get to an end, however that might look. Ultimately I still needed a board for my upcoming travels.

After researching the low-profile market, I went ahead to get Choc sockets, switches, and keycaps. Here’s the BOM:

Kailh Hot Swappable Low Profile 1350 PCB Socket (50pcs)$15.00
Chocfox CFX Low Profile Keycaps (50pcs)$25.00
Sunset Tactile Choc Switches (50pcs)$55.00
Shipping & forwarding$15.00

As anticipated, I spent another USD 110 to be able to make use of the Choc board. While I would have preferred the LowproKB Ambients Sunrise – 40g silent tactile low profile switches – I couldn’t get them and hence settled for the regular Sunset tactiles. As for the keycaps, I picked the cheapest I could find, to not have to type on the plain switch stems. Eventually I upgraded to keycaps from Work Louder, as the learning curve on a new layout without legends was too steep for my taste.

The Corne V3 (Choc)

The "Kunai" Corne V3 Choc + Chocfox CFX Low Profile keycaps

Even with all the hurdles along the way, I am positively surprised with the preliminary result. The board looks very HATSU-ish, but a lot more compact and, more importantly, lightweight, at only 434g including the Kunai case! Even with the unfinished 3D print and different switches and keycaps than I initially anticipated, I liked the aesthetics.

The "Kunai" Corne V3 Choc + Chocfox CFX Low Profile keycaps


The Corne V3 Choc + Work Louder wrk. Daily keycaps

The software side was a bit finicky. Peg, the firmware recommended by Boardsource did not work for me. I experienced odd glitches while typing and the firmware felt very sluggish and took a noticeable amount of time to boot – probably due to it being a MicroPython implementation.

I hence decided to go for good ol’ QMK, with VIA enabled. I built the firmware using the following config:

VIA_ENABLE      = yes
LTO_ENABLE      = yes

To build the firmware for the RP2040 the following command worked:

qmk compile -kb crkbd/rev1 -km via -e CONVERT_TO=blok

The resulting uf2 file could then be copied onto each BLOK’s RPi volume, which can be mounted when powering on the MCU with the Boot button pressed.


The Corne V3 Choc + Work Louder wrk. Daily keycaps

The typing feeling is interesting yet still a bit challenging, being new to that sort of layout. Compared to my other keyboards, the sound of the Corne is less appealing. However, the Kunai case improves the sound significantly, adding some depth to it. I might add silicone dampeners when I’m done with the case to make the sound even more thocky. Overall the typing feeling is nevertheless okay, especially for a board of this size.

To have an easier start I replaced the transparent Chocfox keycaps with Work Louder’s wrk. Daily caps, which I had ordered after struggling with the clear ones for a bit. Even though I’m still using a QWERTY layout, having legends as a reference point helps immensely with orientation when switching layers. As soon as I master all layers above 0 I will throw on the transparent keycaps again, as I find their rougher texture and their aesthetic superior to the Work Louder set. The wrk. Daily remind me too much of the MacBook’s awful keyboard.

The Corne V3 Choc + Work Louder wrk. Daily keycaps @ Star Labs StarBook Mk VI

The end… right?

Well, not quite. At the end of March, I received a message from my forwarder informing me that a package was ready for pick up at my local delivery point. As I didn’t expect anything I went through my e-mails to see whether there was a long-forgotten groupbuy or raffle that might have finally shipped, but I couldn’t find anything. A few days later I went to pick up the package and was surprised to see the sender on the label: Boardsource.

“What the …”, I remember saying to myself while still standing at the counter, waiting to pay another $15 in forwarding. As you might have guessed, for whatever reason I received the package containing the Corne V3 Cherry kit.

I checked the tracking ID on the label and saw that it was a different one than the package that got returned to Boardsource due to the wrong address. It seemed like Boardsource sent the package out another time, but this time with the correct address. I didn’t know whether it was a mistake or whether they did it on purpose at that point, but it felt like destiny was having a good time giggling at this whole situation.

I went back into my e-mails – this time on a freshly built Corne V3 Choc – and typed away:

Hey there again Quinn

I have just picked up a package from my forwarder and am now holding the Cherry kit from Boardsource in my hands. I don’t know how the package ended up here, and whether it was intentional or unintentional on your end, but given that I have now received what I had initially ordered, I have purchased another gift card ($75) in your store and destroyed the code, to pay in full for the MX board that I finally received.

Best regards,

A few days later, however, a full refund of the second voucher hit my credit card, without any response from Boardsource whatsoever.

N.B.: While the length of the Boardsource experience chapter exceeded my intention, I found it important to be transparent and show both sides of the story. Even though there certainly are a few bad apples in the keyboard community I don’t think Boardsource is one of them. In my particular situation, it seemed like fsck-ups just kept piling up, and seemingly due to internal changes, communication was chaotic. Having that said though, the quality of the hardware that I received from them is top-notch.

The Corne V3 (Cherry)

The "Kunai" Corne V3 Cherry

Building the Cherry version was no different than the Choc version and due to the practice I got at that point (heh) I was able to finish the build within a few hours. I went ahead and removed the Choc variant from the Kunai case, to mount the finished Cherry build. I added Gazzew Boba U4T (RGB tops) switches, that I had modded with 78g SPRiT MX Complex springs and lubed with Tribosys 3204. For the keycaps, I used the ePBT x GOK Kuro/Shiro R3 set. As soon as I’m more fluent with the new layout, I’ll probably change it for one of my MT3 sets, or maybe even a new MTNU set.


The "Kunai" Corne V3 Cherry

The software side is identical to the Choc version. I used the very same QMK build to flash the MX version and it worked out of the box. I could even use the same layout in VIA, by saving it as a JSON and loading it onto the Cherry board.


The "Kunai" Corne V3 Cherry

The typing feel is on a different level. The Bobas sound and feel insanely good, and with the Kunai case, the whole build has a fair amount of thocc to it. Even though I’m not a big fan of the Cherry profile, the PBT keycaps feel pretty damn good. With the Corne only making use of R2, R3, and R4, the profile feels more balanced than on a regular keyboard. I do however use R1 artisans for the upper left and right keys, to make it easier to distinguish them from the rest. On my layout, the upper left key is tab on layer 0 and esc on all layers above, and the upper right is backspace on layer 0 and delete on all layers above. Especially when mistyping long numbers – which are positioned on the qwertyuiop keys on layer 1 – I found the layer 1 switch from backspace to delete to be cumbersome. I will probably continue adjusting the layout to make it feel better for someone who’s used to the HHKB layout.

If you’d like to give it a go, you can get the VIA JSON file here.

The "Kunai" Corne V3 Cherry

The end.

I haven’t yet sanded, primed, and painted the Kunai case, but I was able to make the PCBs fit by cutting a few rough edges with a box cutter. I’m planning to use a Dremel to smoothen the surface, then apply white Tamiya surface primer and finish the parts with Tamiya TS-81 Royal Light Grey – the same color as my custom Ultra-Portable Data Center. As I don’t have the tools nor spray paint available to me right now, this last step is going to have to wait, though. I’ll be publishing the final result in a dedicated post.

The overall fun factor of this board is immense. Building, as well as using it is a joy, as soon as you overcome the initial frustration phase of the 40% split layout. Being familiar with a 60% HHKB layout definitely helps with the somewhat steep learning curve. If you’re not touch-typing (ten-finger typing), or not doing it consistently, this keyboard is a great way to force you into doing so. However, depending on your typing experience, it might be a throw into uncomfortably cold waters.

If you’re looking to build this board yourself, be aware that it will get expensive fairly quickly. Even though most people in this hobby are probably used to boards running upwards of $500, if you compare the result of the ~USD 250 Corne build with e.g. a similarly priced Mode Tempo, you will find that the Corne looks, feels and sounds inferior to the Mode. The perceived value of a keyboard like the Corne is however not necessarily in the looks, feel, or sound, but rather in what it is: An ultra-portable, lightweight, ergonomic split keyboard.

Heads up: The Corne V4 was just released. If you’re looking to build this iconic keyboard, you might want to check out its latest iteration. Bear in mind though that it might not be compatible with the Kunai case.

The "Kunai" Corne V3 Cherry


What are the keycaps?

  • Choc: Chocfox CFX Low Profile, Work Louder wrk. Daily
  • Cherry: R3 ePBT x GOK Kuro/Shiro PBT

What are the artisans in the top left and right corner of the Cherry Corne?

They’re the polished variant of the RAMA Hawk artisan from the GMK Stealth set.

What switches did you use?

  • Choc: Sunset Tactile Choc
  • Cherry: Gazzew Boba U4T (RGB tops) switches, modded with 78g SPRiT MX Complex springs and lubed with Tribosys 3204

What’s the coiled, white USB-C cable?

It’s the Deepwell cable with chrome aviator, from Space Cables. As the whole pre-order process was a mess I do not recommend ordering from Space Cables/Space Holdings, though.

Are you going to replace the TRRS cable?

Yes, in fact I ordered a replacement on Aliexpress, which unfortunately was DOA. I dismantled it thinking it’s just an issue with the wiring, however it was an issue inside the angled TRRS connector plug and hence unusable. I will give another seller a try.

Which board do you prefer?

The Cherry board. It’s great how compact the Choc board is, but I detest typing on flat keycaps. If you like the typing feeling on a laptop, however, you will probably love the added travel and tactility of the Choc version, especially with the Work Louder keycaps.

Is the Kunai comfortable without palm rests?

It’s not uncomfortable, let’s put it that way. It’s a little on the higher end, but still within the boundaries of comfort. With MT3 or SA profile keycaps I could imagine it being too high however. I might end up designing and 3D printing palm rests that blend into the Kunai shape.

Can you make a sound test?

As soon as I have finished the case I will upload YouTube/Odysee videos with sound tests.

What does Kunai mean?

As I’m not the original designer of the case, I can only speculate that they referred to the Japanese tool named 苦無:

A kunai (苦無, kunai) is a Japanese tool thought to be originally derived from the masonry trowel. The two widely recognized kinds are the short kunai (小苦無 shō-kunai) and the big kunai (大苦無 dai-kunai). Although a basic tool, the kunai, in the hands of a martial arts expert, could be used as a multi-functional weapon. The kunai is commonly associated with the ninja, who in folklore use them to climb walls.



180kG, aNd HoW mUcH dO yOu BeNcH?!

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