this is only tested to come up to the REPL & mount CIRCUITPY. Pin
assignments should be right but were not double-checked. The screen
is unsupported so far.
This board depends on the I/O pull ups for the I2C bus (verified by
schematic) so this adds a compile time option that enables pull ups
for ANY i2c bus on a board.
* Fix flash writes that don't end on a sector boundary. Fixes#2944
* Fix enum incompatibility with IDF.
* Fix printf output so it goes out debug UART.
* Increase stack size to 8k.
* Fix sleep of less than a tick so it doesn't crash.
