# Flashing your Frimware **URL:** \ **Category:** Software\ **Created:** [December 8, 2014, 7:54am UTC](https://forum.lulzbot.com/t/flashing-your-frimware/1053 "2014-12-08T07:54:58Z")\ **Posts on this page:** 5\ **Page:** 1
**Author:** ![Theycallmejohn](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/theycallmejohn/32/17_2.png) [@Theycallmejohn](https://forum.lulzbot.com/u/Theycallmejohn)\ **Post date:** [December 8, 2014, 7:54am UTC](https://forum.lulzbot.com/t/flashing-your-frimware/1053/1 "2014-12-08T07:54:58Z")
Hello All, So I know the link below describes how to re-flash your firmware but I have no experience with Arduino or marlin. I do have a little programing experience from college. (All engineers have to take some). Does anyone know a more comprehensive guide on how to re-flash your firmware because I am lost. I have an AO-101. [https://www.lulzbot.com/support/re-flashing-your-3d-printers-firmware](https://www.lulzbot.com/support/re-flashing-your-3d-printers-firmware) John ---
**Author:** ![Orias](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/orias/32/3_2.png) [@Orias](https://forum.lulzbot.com/u/Orias)\ **Post date:** [December 8, 2014, 5:41pm UTC](https://forum.lulzbot.com/t/flashing-your-frimware/1053/2 "2014-12-08T17:41:26Z")
Basically, you’ll do the following: Download the firmware: [http://download.lulzbot.com/AO-101/software/current/firmware/Marlin.tar.gz](http://download.lulzbot.com/AO-101/software/current/firmware/Marlin.tar.gz) Extract (unzip) the package so you have a folder called “Marlin”. Install the Arduino IDE: [http://download.lulzbot.com/AO-100/software/2012-Q2/Windows/arduino-1.0.1-windows.zip](http://download.lulzbot.com/AO-100/software/2012-Q2/Windows/arduino-1.0.1-windows.zip) Open the Arduino IDE FInd the tab “Configuration.h” Find the line “#define DEFAULT\_AXIS\_STEPS\_PER\_UNIT {50.25,50.25,756,408} // default steps per unit for AO-101” Change the 408 value within {} to your specific extruder steps per unit (found on your Test Acceptance Sheet) Save the changes Plug in the printer and power it on In the Arduino menu, select Tools \> Serial Port and select the port for your printer In the Arduino men, select Tools \> Board and select “Arduino Mega 2560 or …” Select File \> Upload to compile the sketch into firmware, then automatically upload to the board. If you have any questions please feel free to contact the support team at [Support@LulzBot.com](mailto:Support@LulzBot.com). Why are you reflashing the board? ---
**Author:** ![Theycallmejohn](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/theycallmejohn/32/17_2.png) [@Theycallmejohn](https://forum.lulzbot.com/u/Theycallmejohn)\ **Post date:** [December 8, 2014, 9:41pm UTC](https://forum.lulzbot.com/t/flashing-your-frimware/1053/3 "2014-12-08T21:41:35Z")
Orias thanks for taking the time to lay that out. I will try it tonight. I promised someone I would test print a couple prototypes, then my hotend died. So I bought a JHead and installed it until I can get my Budaschnozzle working again. It is my understanding that I need to re-flash the board in order to update the thermistor table. ---
**Author:** ![Orias](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/orias/32/3_2.png) [@Orias](https://forum.lulzbot.com/u/Orias)\ **Post date:** [December 10, 2014, 10:24pm UTC](https://forum.lulzbot.com/t/flashing-your-frimware/1053/4 "2014-12-10T22:24:09Z")
Yup! That’s correct! Make sure you make the right thermistor selection. The section to look for is: ```nohighlight //=========================================================================== //=============================Thermal Settings ============================ //=========================================================================== // //--NORMAL IS 4.7kohm PULLUP!-- 1kohm pullup can be used on hotend sensor, using correct resistor and table // //// Temperature sensor settings: // -2 is thermocouple with MAX6675 (only for sensor 0) // -1 is thermocouple with AD595 // 0 is not used // 1 is 100k thermistor - best choice for EPCOS 100k (4.7k pullup) // 2 is 200k thermistor - ATC Semitec 204GT-2 (4.7k pullup) // 3 is mendel-parts thermistor (4.7k pullup) // 4 is 10k thermistor !! do not use it for a hotend. It gives bad resolution at high temp. !! // 5 is 100K thermistor - ATC Semitec 104GT-2 (Used in ParCan) (4.7k pullup) // 6 is 100k EPCOS - Not as accurate as table 1 (created using a fluke thermocouple) (4.7k pullup) // 7 is 100k Honeywell thermistor 135-104LAG-J01 (4.7k pullup) // // 1k ohm pullup tables - This is not normal, you would have to have changed out your 4.7k for 1k // (but gives greater accuracy and more stable PID) // 51 is 100k thermistor - EPCOS (1k pullup) // 52 is 200k thermistor - ATC Semitec 204GT-2 (1k pullup) // 55 is 100k thermistor - ATC Semitec 104GT-2 (Used in ParCan) (1k pullup) #define TEMP_SENSOR_0 7 #define TEMP_SENSOR_1 0 #define TEMP_SENSOR_2 0 #define TEMP_SENSOR_BED 7 ``` and change the line: ```nohighlight #define TEMP_SENSOR_0 7 ``` to match whatever thermistor shipped with your j-head. Don’t forget to update your extruder steps per unit. Make sure that your hot end reads room temperature when you first turn on the printer after reflashing- it should read around 20-25C. When you test, make sure to do so in stages- Heat to 50C, then 100C, then 150C, etc. Better safe than molten! ---
**Author:** ![Theycallmejohn](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.lulzbot.com/theycallmejohn/32/17_2.png) [@Theycallmejohn](https://forum.lulzbot.com/u/Theycallmejohn)\ **Post date:** [December 23, 2014, 4:24pm UTC](https://forum.lulzbot.com/t/flashing-your-frimware/1053/5 "2014-12-23T16:24:05Z")
Thanks Guys! Everything worked out great re-flashing the software. Back up and running!