I just programmed my LPC2148 for reading out my Xbox360 Nand and stumbled over some problems, here the details:
I am using an USB2Serial Adapter from Digitus, it was configured on COM7 (Check Hardware-Details on Windows).
To program the 2148, a RS232 shifter from Sparkfun was used.
After wiring the shifter and the USB board i tried to program using FlashMagic, but i just received an "Failed To Autobaud" message! Then i recognised that the USB board must be powered somehow, which was not written in the nice Tutorial i was using.
After powering the board via USB FlashMagic was able to erase the memory, but it was not able to program it giving the error: "Operation Failed. (programming - failed to send data to the device)".
Till now i do not know the root cause of this problem, but i found a workaround for this problem because of a forum post. A user suggested to install LPC2000 flash utility and retry it again.
I just installed the utility i got from the web, started it once - and rebootet windows afterwards. After that, flashmagic was working like a charm - programming the LPC2148 was successful!
However, the Digitus USB2Serial Adapter is manufactured by FTDI, the latest drivers for Windows7 can be obtained from http://ftdichip.com/Drivers/VCP.htm!