You're probably on the wrong firmware version for ABL. Check the biqu website to see if there's a version of the firmware specific for use with an ABL sensor. Bigtreetech also has a GitHub with a lot of stuff you can look for it there.
Thanks for answering. I've been looking at Bigtreetech's GitHub and under Firmware the readme.md states that the newest firmware is "Marlin 2.0.6 (Jan 25 2021 13:43:58)", this is older than my 2.1.1. The folder structure under are made with dates as folder names. There is a folder newer than the newest firmware stated in the readme.md. But there is no version number, just firmware.bin in folders named SKR 2-F407, SKR 2-F429 and SKR V1.4. I don't even know what motherboard i have.. On https://marlinfw.org/ they say that the current release is 2.1.2.4. Pretty close to mine, but I'm missing the last digit. So I assume the firmware on my printer is self compiled. I've watched some videos on how to compile my self, but I'm afraid that with my noob-knowledge i could brick the printer.
I bought a bl touch a few years ago. Decent printer. I updated the firmware and added a bl touch. That's when it all went wrong. I now recommend staying away from biqu as their customer service is non-existent. To your problem, as stated by another commenter, get an updated firmware from biqu's site. I compiled my own, which may explain some of my issues. My initial issues came with the probe offset. I dug a deep line in my plate and took several attempts to realize that I need to change my offset only in the machine parameters, not in the abl menu.
Thanks for answering. Found a post on Reddit about getting the BLTouch working on stock firmware, it all went well until the printer stated that "unknown command m851".. I've looked at the firmwares on Bigtreetech's GitHub, but I found it just confusing. The newest I found there is older than mine. After all youtube videos I've watched and all reading i have done, none have mentioned that the offset parameter is just set in machine parameters and not ABL. Thanks for this.
That may have been a quirk due to compiling my own. I believe I did that because I found myself in a similar situation of not seeing a more recent firmware. If you decide to replace this one, I'd recommend an anycubic. Got a Kobra 2 NEO, and it works great straight out of the box. Similar price range, too, $150-$200.
Think I'll try to cook something up, flash it and hope to be able to recover from any failure.. Got the printer a week ago and paid like $80 for it. Looks like the bed isn't 100% flat and sinks a little in the middle so I should be great to have the BLTouch working. Not ready to give up in this one just yet.
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