ROM found in popular chinese USB to Serial chip (CH340)

#1

Post by bytter » Wed, Sep 02, 2020, 1:20 AM UTC

Re: ROM found in popular chinese USB to Serial chip (CH340)

#2

Post by ComputerGuru » Wed, Sep 02, 2020, 1:23 AM UTC

Why is this surprising? In bulk, ROM is cheaper than EEPROM and I’m sure there’s a good amount of USB-related functionality or logic that can be stored there. It’s not a passive device by any means, so I’m not sure why there’s the implied “where it shouldn’t be” in the thread/title?

Re: ROM found in popular chinese USB to Serial chip (CH340)

#3

Post by bytter » Wed, Sep 02, 2020, 1:31 AM UTC

ComputerGuru wrote: post #2

Why is this surprising? In bulk, ROM is cheaper than EEPROM and I’m sure there’s a good amount of USB-related functionality or logic that can be stored there. It’s not a passive device by any means, so I’m not sure why there’s the implied “where it shouldn’t be” in the thread/title?

Indeed... Ryan Ringo (@ringoware) is an experienced reverse engineer. I assume other USB2Serial ICs have been reversed in the past, so I am curious to why he regards this as "something unexpected". I guess we'll find out once the bit extraction is completed.