Pre-configured Marlin for SKR Mini E3 v2 on Ender 3

This is pre-configured package for the 2.x Marlin Firmware for SKR Mini v2 boards on Creality Ender 3. The configuration files were specially crafted to extract the maximum performance of the printer while maintaining the manufacturer recommended settings. The download packages include both the source code and the compiled binary files.

This firmware will not work with 8-bit boards or Creality 32-bit boards.


Extra features enabled over the standard Marlin firmware configuration.

  • Official Marlin Firmware with the latest updates
  • Ready for Octoprint
  • PID adjustments and auto tune from LCD (nozzle and bed)
  • BLTouch using the probe as Z-Endstop or manual Mesh calibration
  • Bilinear bed leveling with multiple slow probing for maximum precision (5x5 array)
  • Filament runout sensor enabled (3-wire sensor, EZOut compatible) - can be disabled from the LCD menu
  • Restore bed leveling after G28 - no need of custom slicer GCode to load the bed level data
  • LCD based bed leveling
  • Z safe homing (avoid hitting the printed parts)
  • BLTouch voltage menu on the LCD (for BLTouch 3.0 and 3.1)
  • Show filament consumption on the LCD
  • Show remaining, elapsed and estimated printing time in the LCD. If the slicer added the time estimations to the GCode, it will use the slicer information.
  • Power loss recovery - can be turned on/off from the LCD
  • Babystepping
  • Arc support (G2/G3)
  • Bezier curve support (G5)
  • Support for level test (G26)
  • Adjusted the filament change settings for the official Ender 3 bowden tube length
  • Customized menus with the "famous" Heat and Level command
  • Pins debugging (M43)
  • Advanced pause - filament change (M600)
  • Hot End idle timeout - turn off the heater after 5 minutes
  • Host Action commands - enhanced Octoprint integration
  • Homing bump - extra precision to the end switches
  • Adaptive step smoothing
  • Probe offset wizard
  • Enhaced serial float precision - for Octoprint and external LCDs
  • Detailed position data (M114)
  • Soft reset via serial (using KILL or ^X)
  • UTF Filename support for SD Cards
  • Linear Advance + S-Curve acceleration (experimental).

Note about the bed leveling strategy

There are two ways to perform the automatic bed leveling, the first is before every print and the second is only when necessary. Based on my experience with the Ender 3, it's better to do an extremely precise bed leveling when necessary instead of a simpler one before every print. This firmware configuration reflects this choice.

Unified Bed Leveling (UBL) is not recommended and will not be implemented. This feature adds a lot of complexity but does not bring any significant advantage in comparison with the bilinear bed leveling in cartesian printers (delta is another story).

If you want to do quick/imprecise bed leveling before every print you will need to reconfigure the firmware.

BLTouch comments:

  • BLTouch is a convenience for Ender 3 users but not mandatory. Mesh Bed leveling does exactly the same without the hardware additions and does not take much longer to perform.
  • BLTouch 3.0 is problematic, try using higher (3.1, for example) or lower versions (1.x or 2.x).
  • BLTouch sensors are low quality devices and are very susceptible to wiring related problems.
  • Bed level failing is not a problem with the firmware! The only thing you can do from the firmware perspective is setting the correct voltage (you can use the LCD menu).

Note about new version updating strategy

I tend to be very conservative regarding new Marlin versions. The "stable" versions on their website are not that stable at all and installing every minor release can cause more problems that solutions.

New versions of this firmware package will be released according the following criteria:

  • Critical bug fixes: problems that could crash or damage the printer. Small bug fixes like text labels or in features not related with the printer and/or the enabled features will be ignored.
  • Build version increases,, will be ignored unless there are critical bugs to be fixed.
  • Minor version increases: 2.0.6 to 2.0.7 will be released after after I test the version for a few weeks in my printer.
  • Major version increases: 2.0 to 2.1 will depend on what changed and if the hardware supports.


  • SKR Mini E3 v2.0 32-bit board
  • For BLTouch enabled printers:
    • Z-stop switch removed and the BLTouch endstop wires (black and white) connected to the Z endstop pins in the motherboard
    • IMPORTANT! BLTouch tip height must be adjusted according to the official instruction manuals. There are different BLTouch sensor clearances and the YouTube videos tips are wrong most of the times
  • For printers with filament sensor:
    • 3-wire sensor plugged in the E0-STOP port (EZOut compatible)
  • Microsoft Visual Studio Code only if you plan to compile and install from the source code
  • PlatformIO IDE extension installed on Visual Code only if you plan to compile and install from the source code
  • Pronterface (optional): send custom G-Codes to your printer from the USB interface. Very useful to find errors and calibrate the printer. Octoprint does the same.

Instructions for installation from the Source Code

  1. Download and install Visual Studio Code.
  2. From Visual Studio Code extension menu, install the PlatformIO IDE.
  3. With all requirements running, unpack this entire Marlin source code downloaded from the link below to a folder.
  4. From Visual Studio Code select File->Open folder and select the folder where the platformio.ini file is located. Attention! Use the "open folder" command, not the"open file".
  5. Select Terminal->Run Task->Build . It will take a few minutes for the system to download all dependencies and compile the code.
  6. If the code compiled properly you will see something like this in the terminal: "=== 1 succeeded in 00:00:30.050 ===".
  7. Copy the file "firmware.bin" from the folder "YOUR_PROJECT_ROOT\.pio\.pio\build\STM32F103RE_btt_USB\" to the printer SD card
  8. Backup the current firmware from the card by copying the file "firmware.cur" (if exists) to a folder in your computer. Do this before inserting the SD card back to the printer.
  9. Insert the card in the printer and reboot to update the firmware

Instructions for installation from the binary files

  1. Download the package appropriate to your hardware configuration.
  2. Open the ZIP file and extract the "firmware.bin" from "\.pio\build\STM32F103RE_btt_USB\" to an SD card (NOTE: This folder might be hidden in some operating systems)
  3. Insert the SD card in the printer and reboot to update the firmware.

Post-installation configuration

  1. Manually pre-level the bed! This is important because the BLTouch has limited max/min detection ranges and the print quality can be affected if the Z-Axis moves too much (even without BLTouch).
    1. Cool down the bed and the nozzle. Heating should have little to no effect on this specific procedure.
    2. Disable stepper motors using the LCD menu command.
    3. Place a credit card on one the bed, the thickness of the card will be used as a reference distance.
    4. Turn the Z axis with your hand until the nozzle hits the credit card.
    5. Move hot end to several positions of the bed, starting from the 4 corners. For each position, adjust the bed level knobs to keep the nozzle at the credit card thickness distance from the nozzle. This is what you would do in manual calibration but instead of using a paper you will use the card for convenience. The card thickness does not matter because the BLTouch probe will redefine the Z reference.
  2. Heat the bed to the printing temperature and run the bed level command from the LCD (Motion -> Bed Leveling -> Level bed) or use the G29 GCode or the Heat and Level command from the custom menu (recommended). Note that the Heat and Level command waits 2 minutes after the bed is hot to allow the mounted surfaces to expand/contract properly.
  3. Save the settings using the LCD menu or the M500 gcode (if you used the Heat and Level custom command, they will be automatically saved).
  4. After enabling the bed level, print something large and flat to adjust the Z offsets. The nozzle tends to be far from the bed until you adjust the offset to a negative value (Configuration -> Probe Z Offset). Don't forget to save the settings after the print to keep the offset in the memory.
  5. Optional steps:
    1. Adjust the extruder steps (menu avaliable in the LCD)
    2. Calibrate the hot end and bed PIDs (menu available in the LCD)
    3. Set the linear advance K-Factor using Marlin tool.
    4. Set the desired Z fade distance for the bed level compensation. I recommend around 5mm for the Ender 3. (menu available in the LCD: Motion->Bed Leveling)
    5. Save all previous setting to the EEPROM.

Troubleshooting and FAQ

  • I don't want to use the Linear Advance feature: Just set the K to 0 in the LCD menu.
  • The S-Curve should not be enabled with Linear Advance: This firmware is using the experimental mode that allows both features to co-exist. After many hours printing with both features enabled I didn't noted any problems with this printer/board. If you set the K to 0, only S-Curve acceleration will be used.
  • BLTouch is probing outside the bed or too far from the edges: Adjust the probe offsets (Configuration -> Advanced settings -> Probe Offsets )
  • Bed or nozzle are not centered: Please adjust the home offsets (M206) and the hotend offsets (M218).
  • Why not use the ENDSTOP_INTERRUPTS feature? Bigtreetech did not enabled this feature in the original firmware. I am still trying to figure out the reason for that.
  • Want to go back to the previous firmware: If you did the backup of the original firmware, just rename the firmware.cur file to firmware.bin and then put inside the SD card and reboot the printer.
  • Does it supports TFT35, TFT43, TFT50, TFT70, etc... displays: Yes, no modifications required. Please remember that such displays have their own firmware and not all functions will be reachable from the graphical interface unless you use the "Marlin mode".
  • Does it work on the Ender 3 v2? If you are using the SKR E3 Mini v2.0 board and the CR-10, Ender 3v1 display or the TFT35 display (or similar) it will work. If you are using the SKR board with the standard display the answer is no (different wiring).
  • I don't have a filament sensor: No problem, the filament sensor is a switch that closes when there is no filament. If there is no switch installed, the printer will ignore that. If you want to install a switch, just plug the wire and it will work instantaneously (unless it is a rare switch that works with an inverted signal).
  • Why the downloads are so big? Because I included all pre-compiled libraries with it. This allows you to recompile the firmware with a single click in the compile button. Before I included the libraries, many users had problems downloading them.
  • Temperatures are going up and down like crazy: Please calibrate the PID for the bed and for the nozzle, there is a menu in the LCD for that. Alternately you can use the PID Autotune (M303).

If you have problems compiling the firmware...

I can compile the firmware for you. Please see here for more details.

Other Marlin downloads for Ender 3

Version (Jul 3, 2021)
Ender 3 with SKR Mini v2.0 boards
File size
178 MB
SHA256: 7C5F788E1F6D813F8EC8031CD976B9C931B85908EC4D334D4D4AC210F3361A57
SHA256: DA9B86E7DFDAC61D9C3B9D19ECB65A1F13C591B70D663F2A6BE2D69464ED311A

Post Categories


Submitted by Alessio Fusaro on Sat, 10/23/2021 Permalink

You did a great job! Thank you! I use hot-end and direct drive extruder micro swiss and Satsana fan duct on Ender3 PRO. With marlin 1.x I had to set a non-standard Y_MIN_POS, in marlin 2.x I couldn't get it to work... but the easiest solution was to move the sensor end-stop physically and now everything works perfectly

Submitted by delfos on Wed, 10/20/2021 Permalink

So a good while back, my printer crashed mid print. After that, it was printing fine. Today, the printer is freaking out. It crashed twice on the same file.

the printer was showing the normal home screen with a bunch of weird lines and stuff flashing around. any idea what is causing this?

Submitted by joe on Thu, 09/23/2021 Permalink

I have skr mini e3 v2 and a tft70 display.  after inserting sdcard with this firmware i got a quick message i couldnt capture saying mismatch however it seems to have loaded, but another quick message said auto leveling failed to load.

i do not use bltouch.  is there any steps i need after flashing?

If you downloaded and installed the Mesh Bed Leveling file (no BLtouch), you need do do a "manual" bed leveling on the LCD. Select 'Level bed', on the move menu.

It will move the nozzle around the bed and you use the dial knob to adjust the Z level to a piece of paper. After all the points are measured, save to EEPROM. It will auto load this on start-up.

Submitted by kolodziej on Thu, 09/23/2021 Permalink

Hi, thank you for a great firmware. I have creality bltouch with all wires in one connector. Is there any way to use whole bltouch connector instead of z-stop pins? I don't want to splice the wire.

Hi. I have a printer setup just like yours. I use the BLtouch with all the wires on the Probe connector.

If your wiring is done right, according to the diagrams on both the SKR Mini e3 v2 and on the probe itself, it will work with just two config changes.
BLtouch and Creality CR-touch are wired the same on the SKR board, I did check the probe pins diagram to see if they match with the SKR probe ports. They did.

Bellow are the changes that worked for me.

For them to work I needed to change only two lines in Configuration.h

  1. Changed/commented line:




  2. Changed/uncommented line:

    //#define USE_PROBE_FOR_Z_HOMING



Then compile the firmware and it will (1) use the probe on the 5 pins Probe port, and (2) use the probe for homing Z.

If your endstop is still connected to the board, move is lower so that it won't trigger before the CR/BL-touch.


Should work for  you as well.

I have a problem with HOTEND_IDLE_TIMEOUT feature. Sometimes my Ender 3 PRO with SKR Mini e3 v2 stops in the middle of a print process and it reports the "hotend idle timeout" error... this is strange because surely 5 minutes have not passed since the last GCODE command.
Do you know if this is a Marlin bug and if there is a fix for that?
Meanwhile, I'm disabling this feature.
Thank you for sharing your very good customization.

Submitted by joe on Thu, 09/09/2021 Permalink

Hello, will this firmware work just as well with an ender clone like auila x2 using the mimi e3 v2 board?  Thank you.  Its still on the bugfix 2.0 and seems to work fine.

Make sure they use the same thermistor type that is used on the Ender (type 1), as that is set in the Marlin config files.
It's the only thing that comes to my mind that *may* be different in a clone.

Use alex's firmware for the aquila. That's what i'm using on mine and pretty much has every feature you need for the aquila. I don't have a bl touch on that one but if you do it's just a few changes to the firmware in vsc

Submitted by Jim Lewis on Mon, 09/06/2021 Permalink

After installing the pre-config binary on Ender 3 with MKR mini V2, scrolling files is unbearably slow. Any solutions?

Do you have too many files in the SD card? If the quantity is too high the filenames will take all available RAM and the performance will degradate.

Disable the settings below to reduce the RAM use:

  // This allows hosts to request long names for files and folders with M33

  // Enable this option to scroll long filenames in the SD card menu


You beautiful bastard, I spent MONTHS trying to get ABL to work (one side too low, the other too high) and for whatever reason, yours works PERFECTLY. I can't thank you enough man. I've bookmarked your page and now regard you as the Go-To-Source for firmware knowledge, screw everywhere else.

Submitted by Stefano on Fri, 09/03/2021 Permalink

Hi, I found your firmware searching for a version to fix my Ender 3. I had a working version from morningreis and updated to his but now all my axes try to home to the opposite side,  crashing every time.

Your firmware seems very good but I have an SKR miNI e3 V1.2. What should I change to compile it for this board?
Thank you

Submitted by Noah on Tue, 08/31/2021 Permalink

My printer worked great for a year. Then suddenly, one day, it went crazy. I spent three months trying to get it going again, all kinds of firmware etc. I decided it had to be a bad BLTouch, Bad SKR board or something. Then, I randomly found this firmware from a reddit link. I kid you not, it worked out of the gate. Not too mention, all the extras and custom options.

Thank you! My printer was literally hours away from the garbage.

Awesome work.

Submitted by Ciro on Wed, 08/04/2021 Permalink

Hi again! Thanks and great work on the updates, as always!

I haven't tried the update yet, but I noticed that you have set

"default_envs = STM32F103RE_btt_USB"
how does it affect the USB connection to Octoprint/Octopi as opposed to STM32F103RE_btt?


The USB mode exposes the SD card as a mass storage device to the USB host. It helps you to visualize the files in the SD from Octoprint.

It has no impact on the G-Code transfer between devices.

Can't thank you enough for this!  I only recently picked up an Ender 3 Pro, then started upgrading it, starting with the BTT SKR Mini E3 v2.  I got the upgraded board because I wanted to have an easier time performing updates and firmware changes, but when ended up happening is I traded one time sink (opening up the board enclosure and fiddling around with bootloader hacks) for another (screwing around with two config files and no clear guidance as to what does what).

I thought I had found the answers with a couple of walkthroughs presented by otherwise knowledgeable YouTubers, but then I started running into weird problems with the printing process that simple made no sense and seemingly had no answers.

Then I stumbled on this blog and realized I had made a couple of errors in terms of BLTouch settings, and with sound settings as well.  Who knew that enabling the speaker would activate a bug that prevented the part cooling fan from running at all?!

Anyway, I think I'm still trying to come to terms with the actual state of the industry, which I had assumed to be a lot more mature than what it apparently is.  But, thanks to your work, I don't need to spend a bunch of time becoming an expert in all the behind-the-scenes settings.  That will come in due time, AFTER I've had a chance to start producing some of these print ideas I've had lurking in my archives for years.  :D

Submitted by Spensio on Tue, 07/27/2021 Permalink

After upload this firmware to my ender 3 pro i can't connect with USB to repetier host or any other porogram like cura etc... How can i solve it ??

The USB works.  Please double check the baud rate for the connection and make sure you don't have any accessories conflicting with it.

Tryed at simplify:

Attempting connection at \\.\COM11...

Testing plaintext communication protocol...

Testing binary communication protocol...

Testing alternate communication protocols...

Connection failed.


Same is at other program. Before i had connect at COM4 but now when i plug printer into laptop have only com11 and cant connect.


Submitted by Amdresen on Thu, 07/22/2021 Permalink

I tried to debug, but I become an error.



"No emulators connect via usb

Do you want to connect to a J-Link via tcp /IP instead ?

Identifier may be one of the following

Blank: Select from a list of available J-Links

IP Adress

Serial number 281100001"


What can I do? Please  help


Submitted by Destin732 on Tue, 07/20/2021 Permalink

I set the temp of the bed to 60 on display, the bed heats to 50 and a few minutes later the alarm goes off for heating issue. 


You need to calibrate the PID for the bed. Use the following GCode:

M303 E-1 S60 C10 ; Run PID autotune on bed for 10 cycles
M304 P558.37 I109.94 D708.99 ; Replace with your results from autotune. These are what I got for mine.
M500 ; Save settings to EEPROM

Never run any firmware update without calibrating the PID for the bed and HotEnd.

Submitted by corey on Sat, 07/17/2021 Permalink

I really appreciate what you've put up here.  I just found it from a random search, but I'm not sure why this isn't a well known reference in the subreddits and elsewhere.  After installing a BLTouch (on an Ender 3 Pro w/ SKR E3 Mini V2) I was having issues with failing to home with no z-axis downward movement with the BTT official binary.  I've built Marlin before, but was hesitant to reconfigure and rebuild for the BLTouch until I checked the installation out with BTT's binaries, but their binaries never worked for me.  I had nearly given up on the BLTouch when I found this load and it just worked!  Thanks so much for providing the resources, especially your whole Marlin configuration.  I can check all of your settings against my own now. 

Submitted by Hartmut on Sat, 07/17/2021 Permalink

Hi Daniel,


Thank you for your effort to adapt the Marlin firmware for the BTT SKR mini E3 V2.0 and the BL Touch.

now it works for me too.

It is a shame that BTT is not able to provide this service for its components.




Submitted by Peter on Wed, 07/07/2021 Permalink

First off, this is fantastic work! Thank you so much for your efforts to make this! It has saved me so much time.

Do you plan on updating this?(I realize I'm a year late...) I am trying to run the BTT Smart Filament sensor, and it requires the FILAMENT_RUNOUT_DISTANCE_MM to be enabled in the firmware. Otherwise the printer detects a runout as soon as a print starts. I have to turn off the sensor in order to print.  Is that something you would consider revisiting?

Regardless, thanks again for your efforts!

Submitted by Kamil on Thu, 06/03/2021 Permalink

Hello, where i can change notification on LCD showing , when i plug in SD card or plug out?For example "Media inserted".

Submitted by koolblue57 on Fri, 03/12/2021 Permalink


I've run into a slight issue with your firmware when I try to level the bed, auto home, or just move the z-axis down with the LCD the z-axis refuses to move down it only moves up.


I'm using an SKR E3 V2 and Ender 3 pro