<p>There are mainly three reasons for that:</p>

<ol>
<li>Arduino studio settings should be: 

<ul>
<li>Board: Mega 2560 and</li>
<li>Programmer: AVR ISP </li>
<li><strong>and valid COM port</strong>, please see below:</li>
</ul></li>
</ol>

<p><a href="https://i.sstatic.net/C8Xe3.png" rel="noreferrer"><img src="https://i.sstatic.net/C8Xe3.png" alt="Arduino settings"></a></p>

<ol start="2">
<li><p>Please close all slicer's instances (Cura, Slic3r, Repetiter)  and host servers and other software that communicate with the printer as they lock the COM port;</p></li>
<li><p>Please check that the appropriate usb2serial drivers are installed and working - the best way is to start the serial monitor from the Arduino Studio Tools menu and see if there are any. </p></li>
</ol>

CC BY-SA 3.0
2018-04-20T09:05:07.957Z
+1 for mentioning the slicer software in the overview, the slicer is frequently overlooked and certainly got me  a few times wondering why it would not upload!
0scar
CC BY-SA 3.0
2018-04-20T12:17:44.510Z
how about a too-high baud rate?
Roger
CC BY-SA 3.0
2018-04-20T12:26:02.847Z
@Roger the baud rate is determined by board/programmer in Arduino Studio, that means we don't have access to set it.
profesor79
CC BY-SA 3.0
2018-04-20T18:17:51.243Z
4. There is a preloaded task in your Arduino, I´ve seen this several times.
Fernando Baltazar
CC BY-SA 3.0
2018-04-20T08:25:09.537Z
2018-04-20T09:06:22.030Z
2018-04-20T09:06:22.030Z
profesor79
<p>When trying to upload firmware I get the following errors:</p>

<ol>
<li><code>timeout - cannot sync</code>, or</li>
<li><code>port is in use</code></li>
</ol>

<p>What can be the possible sources of these errors?</p>

<firmware>
How to upload firmware to reprap printer?
profesor79
# How to upload firmware to reprap printer?

(Asked by: username_0 on 2018-04-20)

When trying to upload firmware I get the following errors:

1. `timeout - cannot sync`, or
2. `port is in use`

What can be the possible sources of these errors?

**Tags:** firmware

---

## 1 answers

### Answer by username_0 on 2018-04-20. Score: 6 | Accepted answer

There are mainly three reasons for that:

1. Arduino studio settings should be:
   * Board: Mega 2560 and
   * Programmer: AVR ISP
   * **and valid COM port**, please see below:

[![Arduino settings](https://i.sstatic.net/C8Xe3.png)](https://i.sstatic.net/C8Xe3.png)

2. Please close all slicer's instances (Cura, Slic3r, Repetiter) and host servers and other software that communicate with the printer as they lock the COM port;
3. Please check that the appropriate usb2serial drivers are installed and working - the best way is to start the serial monitor from the Arduino Studio Tools menu and see if there are any.

> **Comments:**
> **username_1**: +1 for mentioning the slicer software in the overview, the slicer is frequently overlooked and certainly got me  a few times wondering why it would not upload!  
> **username_2**: how about a too-high baud rate?  
> **username_0**: @Roger the baud rate is determined by board/programmer in Arduino Studio, that means we don't have access to set it.  
> **username_3**: 4. There is a preloaded task in your Arduino, I´ve seen this several times.  

---

