# Arduino Uno/Nano as MCU not supported anymore? **URL:** \ **Category:** General Discussion\ **Created:** [August 2, 2024, 8:19pm UTC](https://klipper.discourse.group/t/arduino-uno-nano-as-mcu-not-supported-anymore/18043 "2024-08-02T20:19:49Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Toni](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/toni/32/13424_2.png) [@Toni](https://klipper.discourse.group/u/Toni)\ **Post date:** [August 2, 2024, 8:19pm UTC](https://klipper.discourse.group/t/arduino-uno-nano-as-mcu-not-supported-anymore/18043/1 "2024-08-02T20:19:49Z")
### Basic Information: Printer Model: MCU / Printerboard: SKR 1.4 and Arduino Nano Host / SBC klippy.log [klippy(21).log](https://klipper.discourse.group/uploads/short-url/v8ZOlUeURH0D9RBUL6Nnh8PkPQq.log) (1.2 MB) _Fill out above information and_ **_in all cases attach your_ `klippy.log` _file_** (use zip to compress it, if too big). _Pasting your_ `printer.cfg` _is **not** needed_ _ **Be sure to check our “Knowledge Base” Category first. Most relevant items, e.g. error messages, are covered there** _ ### Describe your issue: I had a lot of weird bugs over the last months which appeared and disappeared randomly. I was trying out so many different things which never did anything. I always updated everything correctly (or so I thought) via Mainsail or KIAUH. But now I have seen in the logs that only my main MCU (SKR 1.4) got updated and my secondary MCU did not. So I tried to do that manualy via KIAUH. Nope. Not possible. The Firmware is too big. Even when removing everything via the reducing-feature its too big. The Error I get is this: “Version: v0.12.0-272-g13c75ea8 Linking out/klipper.elf /usr/lib/gcc/avr/5.4.0/../../../avr/bin/ld: address 0x800931 of out/klipper.elf section `.bss' is not within region `data’ /usr/lib/gcc/avr/5.4.0/../../../avr/bin/ld: address 0x800931 of out/klipper.elf section `.bss' is not within region `data’ collect2: error: ld returned 1 exit status make: \*\*\* [Makefile:73: out/klipper.elf] Error 1” And so the flashing also fails. Am I hardstuck on an old version of Klipper and need to get a new MCU with bigger memory? … ---
**Author:** ![Sineos](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/sineos/32/18_2.png) [@Sineos](https://klipper.discourse.group/u/Sineos)\ **Post date:** [August 3, 2024, 7:03am UTC](https://klipper.discourse.group/t/arduino-uno-nano-as-mcu-not-supported-anymore/18043/2 "2024-08-03T07:03:06Z")
See if [Cannot build firmware for Arduino Uno - #7 by PCChazter](https://klipper.discourse.group/t/cannot-build-firmware-for-arduino-uno/7041/7) helps ---
**Author:** ![T9Air](https://avatars.discourse-cdn.com/v4/letter/t/e480ec/32.png) [@T9Air](https://klipper.discourse.group/u/T9Air)\ **Post date:** [August 4, 2024, 9:34pm UTC](https://klipper.discourse.group/t/arduino-uno-nano-as-mcu-not-supported-anymore/18043/3 "2024-08-04T21:34:06Z")
some of them use the atmega328p variant, which does not have enough room for the files. ---
**Author:** ![Toni](https://yyz2.discourse-cdn.com/free1/user_avatar/klipper.discourse.group/toni/32/13424_2.png) [@Toni](https://klipper.discourse.group/u/Toni)\ **Post date:** [August 4, 2024, 10:06pm UTC](https://klipper.discourse.group/t/arduino-uno-nano-as-mcu-not-supported-anymore/18043/4 "2024-08-04T22:06:49Z")
But I already get the Error when I make the file. And while doing that, KIAUH doesnt know how much memory my microcontroller has. ---
**Author:** ![T9Air](https://avatars.discourse-cdn.com/v4/letter/t/e480ec/32.png) [@T9Air](https://klipper.discourse.group/u/T9Air)\ **Post date:** [August 4, 2024, 11:26pm UTC](https://klipper.discourse.group/t/arduino-uno-nano-as-mcu-not-supported-anymore/18043/5 "2024-08-04T23:26:20Z")
When you make your file, you tell it what mcu variant you use, which is atmega328p. I have tried using it with that variant and it does not work, however when I have changed the variant it does work. ---
**Author:** ![system](https://global.discourse-cdn.com/free1/uploads/klipper/original/1X/64419bf2aac6639e6ef5cef200dcd456b0a01ac3.png) [@system](https://klipper.discourse.group/u/system)\ **Post date:** [October 3, 2024, 11:27pm UTC](https://klipper.discourse.group/t/arduino-uno-nano-as-mcu-not-supported-anymore/18043/6 "2024-10-03T23:27:02Z")
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