# Cannot compile firmware (Sensorless Homing declared Void)
**URL:** https://forum.lulzbot.com/t/cannot-compile-firmware-sensorless-homing-declared-void/6397
**Category:** Software
**Created:** [December 29, 2018, 5:07pm UTC](https://forum.lulzbot.com/t/cannot-compile-firmware-sensorless-homing-declared-void/6397 "2018-12-29T17:07:53Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@SappySE107](https://forum.lulzbot.com/u/SappySE107)
#### Post date: [December 29, 2018, 5:07pm UTC](https://forum.lulzbot.com/t/cannot-compile-firmware-sensorless-homing-declared-void/6397/1 "2018-12-29T17:07:53Z")
Downloaded the firmware source from lulzbot under the hibiscus (mini 2) folder. I get 61 pages of warnings for all the lulzbot variables being redefined, and an error that “variable or field ‘tmc\_sensorless\_homing’ declared void” Why? If this is a source for the firmware I am using right now, why won’t it compile as it was written?
---
### Author:  [@SappySE107](https://forum.lulzbot.com/u/SappySE107)
#### Post date: [January 3, 2019, 3:04am UTC](https://forum.lulzbot.com/t/cannot-compile-firmware-sensorless-homing-declared-void/6397/2 "2019-01-03T03:04:35Z")
How about an example of a working source for firmware?
---
### Author:  [@supermanny](https://forum.lulzbot.com/u/supermanny)
#### Post date: [January 7, 2019, 5:12am UTC](https://forum.lulzbot.com/t/cannot-compile-firmware-sensorless-homing-declared-void/6397/3 "2019-01-07T05:12:00Z")
The master branch compiled just fine, I used the build script and compiled for every version and toolhead combo this past weekend. There were some benign warnings, nothing that got me worried.
[https://code.alephobjects.com/diffusion/MARLIN/](https://code.alephobjects.com/diffusion/MARLIN/)
---
### Author:  [@Orias](https://forum.lulzbot.com/u/Orias)
#### Post date: [January 7, 2019, 10:20pm UTC](https://forum.lulzbot.com/t/cannot-compile-firmware-sensorless-homing-declared-void/6397/4 "2019-01-07T22:20:43Z")
> [@](#):
>
> How about an example of a working source for firmware?
What operating system do you use? We use GNU/Linux exclusively, but you should be able to use the same tools like make and gcc-avr on your operating system.
Start with the latest source from git: [https://code.alephobjects.com/diffusion/MARLIN/](https://code.alephobjects.com/diffusion/MARLIN/)
Alternatively, grab this zip archive: [http://download.lulzbot.com/Software/Marlin/1.1.9.28/Marlin-src\_1.1.9.28\_193d1f804.zip](http://download.lulzbot.com/Software/Marlin/1.1.9.28/Marlin-src_1.1.9.28_193d1f804.zip)
We prefer to use the build script to compile the all firmware all at once.
If you’d rather use the Arduino IDE, make sure you have the U8glib library installed. Turning on verbose logging during compilation and upload will be helpful as well.
Take these known-good sources, and compile the stock firmware to know that your build environment works. Once you have successfully compiled, minimize your variables by starting your modifications little by little, compiling after a change or two to make sure you’re on the right track.