serial to usb converter

[skimask]

Things don't to well with a usb-serial converter, errors everywhere. I am suspecting that the converter may be adding control characters amongst the output but I'm not sure.

I'd doubt it. USB-Serial converters don't (ok, shouldn't) modify the data and add characters as you suggest.
What does the RAW data look like? Do you have any control of that at either end?

[Ioannis]

Is your communication time critical? Maybe the converter puts some delay in the flow of data.

Ioannis

[BrianT]

I think you are seeing the same effect as I see when trying to run an RS232 boot loader through a USB to serial converter. The boot loader seems to be very fussy about send/receive character delays and some converters, some of the time, work while others don't work ever.

I have even managed to blow up the bootloader through a USB to serial converter and had to reload the bootloader via EPIC.

I suggest you try several different USB to serial converters.

HTH
BrianT