the documentation & and faq claim that the espressobin can be powered over the 5V microUSB. I connected the micro usb connector to a 2A usb wall charger, yet the board does not boot. Did anyone get to boot the espresssobin over the 5V microUSB? Am I missing something?
No it does not. You must use the 12v power supply. I recently proved this to myself. You will be unable to get into the basic console mode without the power supply and the instructions are incorrect for initial start, you will not get to boot into any type of operating system.
There are a desing error in U18 route. You can solve it doing a wrapping between U18(pin 1) and U18(pin 2) if you never use a 12V power supply. If 12V is needed you can add a resistor R=~1MOhm between U18(pin 1) and U18(pin 2).