Create tinygo-flash-errors.md

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Author: soypat

content/docs/guides/tinygo-flash-errors.md

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+---
+title: "Tinygo flash errors"
+weight: 11
+description: |
+  Solving common problems when flashing your first TinyGo program.
+---
+
+Flashing to a port may be a source of pain with a unconfigured computer. Here are some common problems when trying to get your first program on a device.
+
+* [Serial port permission problems (Linux)](#permission-denied-linux)
+
+### Permission Denied (Linux)
+
+This error is usually encountered when flashing your first program, here's a typical error:
+```
+avrdude: ser_open(): can't open device "/dev/ttyACM0": Permission denied
+```
+
+The above error may be followed by `ioctl` errors too.
+
+To fix this we must make sure our user is included in the group with access to serial ports. On ubuntu and Debian this is the **dialout** group.
+
+First we can check if we are not already part of the `dialout` group:
+
+```shell
+groups
+```
+The output should look something like `youruser adm cdrom sudo dip plugdev lpadmin lxd sambashare`. If dialout is not present in the groups we can add ourselves to it with the following command:
+
+```shell
+sudo usermod -aG dialout $(whoami)
+```
+This will add our current user to dialout group. **Log out and log in again to complete the procedure**. You should now be able to flash to your device. 
+
+As a last resort if this does not work you can try to modify the permissions with `chmod`. For the error above we may try `sudo chmod a+rw /dev/ttyACM0` where `/dev/ttyACM0` is the serial port we are trying to flash to.