So, the postman brought me a carambola this morning, and I spent 4 hours trying to get it up.

I have a PL2303 USB to Serial cable, working well and being used for my arduinos and my chumby hacker board. I connected TX to pin 35, RX to 36 and GND to 37. Connected +3.3v to pin 22 and GND to 24. Started screen on my Ubuntu (screen /dev/ttyUSB0 115200), but only got garbage.

Is there something missing?

Try set bitrate to 57600, it should help.

The linux console in my carambola is set for 57600, but bootloader work on 115200.

I was using Arduino as a 3.3V power source. Reading the Arduino docs I realized that 3.3V on Arduino can supply only 50mA, way lower than I need. I will get a real 3.3V power source tomorrow and try again.

I hope you are using a 3.3V TTL level USB to serial converter. The actual USB to RS232 converters use much higher voltages (these can range from -25V to +25V), which is part of the RS232 specification.

Either way you'll need to be able to supply 500mA on the 3.3V rail.

Yes, I am using a 3.3V converter.

And I solved the problem: I was starving my Carambola with a 3.3V/40mA power source. Now I got a dedicated ATX power source capable of 3.3V/10A, plugged everything, and now I am configuring wifi.

Looks like I will have fun.