Four beeps indicates a corrupt CCF. This happens with the Pronto boots and encounters an invalid configuration.

So, some posibilities:

* Is, is the Pronto "crashing" during the download and rebooting with a corrupt CCF? This might also indicate a physical problem with the flash memory.

* Is the CCF you're trying to transfer itself corrupt (or somehow inappropriate for your model) and causing the download to fail part way through?

* Is there a problem with your serial cable or with your PC's serial communications (ie. you're using a USB adaptor) causing the download to abort?