Although usual intention of the original hardware designer is to produce high quality electronics, this cannot always be guaranteed by vendors re-using open-hardware design or altering it in any way.

The purpose of this page is to facilitate board inspection to detect deviations from the original design, which may deliver sub-optimal performance.

Typical causes of failures

• Chip with less memory or lower clock different from original STM32 F405
• Prototype chip (ARM A) with bugs instead of latter silicon revisions (ARM Z, 1, 2, Y)
• Shorts or not enough solder paste
• Bad capacitors causing resets when connecting board over USB
• Bad regulators
• Missing ESD protection diodes on Flexi, Flexi-io or Main port (except Nano which has none by design).