Add troubleshooting information (#15, fix#17)

README.md

@@ -37,6 +37,15 @@ Gettings Started
 
 For instructions and more information visit the [documentation](https://epdiy.readthedocs.io/en/latest/getting_started.html)!
 
+Troubleshooting
+---------------
+
+The following list is compiled from past experiences and GitHub issues:
+ * **The displayed image displays only part of the image.** Make sure to select the correct display type as described [here](https://epdiy.readthedocs.io/en/latest/getting_started.html#selecting-a-display-type).
+ * **The existing image fades / darkens when updating a partial screen region.** Make sure the VCOM voltage is [calibrated](https://epdiy.readthedocs.io/en/latest/getting_started.html#calibrate-vcom) for your specific display.
+ * **The second third of the image is replaced with the last third.** This seems to be a timing issue we could not yet quite figure out the reason for. For a workarround or suggestions please [join the discussion](https://github.com/vroland/epdiy/issues/15).
+ * **The ESP does not boot correctly when external periperals are connected.** Make sure not to pull GPIO12 high during boot, as it is a strapping pin internal voltage selection (https://github.com/vroland/epdiy/issues/17).
+
 Hackaday Project
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