# Klipper issue when connecting to the printer after installation
**URL:** https://klipper.discourse.group/t/klipper-issue-when-connecting-to-the-printer-after-installation/978
**Category:** General Discussion
**Created:** [September 25, 2021, 11:57am UTC](https://klipper.discourse.group/t/klipper-issue-when-connecting-to-the-printer-after-installation/978 "2021-09-25T11:57:40Z")
**Posts on this page:** 2
**Page:** 1
### Author:  [@Pat](https://klipper.discourse.group/u/Pat)
#### Post date: [September 25, 2021, 11:57am UTC](https://klipper.discourse.group/t/klipper-issue-when-connecting-to-the-printer-after-installation/978/1 "2021-09-25T11:57:40Z")
Hi;
I made a fresh new installation of a V-Core printer using the recommended vcoreos on a Raspberry Pi 3B+ connected to a SKR Pro 1.2 which received the RatRig recommended firmware (firmware-btt-skr-pro-12.bin).
I also installed an ADXL345 and I have the following error at the first start of the system:
**mcu ‘mcu’: Unknown command: adxl345\_end**
**This type of error is frequently caused by running an older**
**version of the firmware on the micro-controller (fix by**
**recompiling and flashing the firmware).**
**Known versions: host=v0.9.1-621-gdafb74e3, mcu=v0.9.1-758-gf11acd80**
I have this issue with or without commenting the include for the ADXL345 file in printer.cfg.
I couldn’t find anything when googling this error that’s why I’m here hoping someone could help.
Should I recompile the firmware as mentioned ? And is this done on the Raspberry ?
Thank you in advance.
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### Author:  [@Pat](https://klipper.discourse.group/u/Pat)
#### Post date: [September 25, 2021, 12:28pm UTC](https://klipper.discourse.group/t/klipper-issue-when-connecting-to-the-printer-after-installation/978/2 "2021-09-25T12:28:34Z")
Well, the solution was rather easy but I was too stupid to think about it at first: I only had to update everything to the latest version (klipper, v-coreos etc…).