I've been prototyping with ESP32 based on Mike Rankin's ESP trINKet design, but I love the openness of RISC-V and the SiFive FE310. 

It also may be possible for SiFive to donate quantity 300 for the badge production which would really help given the max budget of $25/badge.

My concerns right now with the SiFive FE310:

1) Will the FE310 run out of SRAM?

Goal: control an e-paper display and receive updates like name of badge wearer from an Android or iOS phone via either BLE or NFC (depending on cost and/or ease of implementation)

2) How can people program the FE310?

Goal: the badge should be useful after the event for other projects. The FTDI programmer chip is too expensive to put on the badge.  It would be great to have a serial bootloader.

I would appreciate any thoughts from the Hackaday.io community, especially anyone that has experience with the FE310 such as @Michael Welling 

Thanks!

-Drew Fustini