How to make ets_printf work in stage2a?

[zdila]

Is there a reason why ets_printf prints nothing from rboot-stage2a.c? It would be nice to have it for debugging purposes.

[raburton]

I can't think of any reason it wouldn't work from there, but we're running code from an area of memory we aren't intended to (it's normally for the flash cache, but isn't yet being used). Maybe the printf function isn't happy to access this area for it's parameters?

[zdila]

Note that ets_putc works there.