In order to dynamically configure a tessel (over BLE for example), I need a small amount of flash that I'm able to read/write. Is there anything like this available on Tessel 1 or 2 or am I forced to purchase the microsd?
Tessel 1 does not have the ability to write to flash from JS.
Tessel 2 has a persistent Linux filesystem.
OK, that's great then. Tessel 2 will be the final platform anyway.