I am assuming that your problem is solved by now.
Please let me know if not.
I have exactly the same problem.
I have a HEX file for my FX2LP.
Under windows 7 64 bits i use a spt file to load the driver and firmware. Every works well.
I go in control center and try to load the hex file to RAM.( the same hexfile).
Then i can use control endpoint and read bulk endpoint.
IF i try to write to the endpoint 0x08 then on the next control endpoint the firmware lock.
Exactly the same requests work when the firmware is load by spt file. but not when hex loaded to RAM.
I have try to reset cpu, reenumerrate , reset endpoint.
Before each request i try to know the STALL status of an endpoint. all are 0 (no problem).
I have try on other system and the result is strictly the same.
What does the cypress console when executing the spt file ? there is a configuration made somewhere more.
Thank you for your support.