Replacing STM32F103CBT6(U2) on the STM32F407G-DISC1

[SidneyCritic]

The U2 on my STM32F407G-DISC1 is shorted and needs to be replaced.
Is the STM32F103CBT6(U2) pre-programmed, or can I just replace it with a new blank STM32F103CBT6 and it gets programmed when you DFU firmware the STM32F407G-DISC1 board.
Hardware isn't a problem for me because I'm a Mech Eng, but how all this software works baffles me, ie, I'm assuming U2 is just a micro and needs code before it becomes functional for whatever it does - lol -.

[SidneyCritic · Accepted solution]

Well I found that I had one of those cheap cut down STM dev(DIY MORE) boards on my shelf, so I swapped out the STM32F407VGT6 LQFP100 and now it works fine through the ST-LINK programmer, ie, the other chip was definitely fried. Other than the annoyance of doing everything manually, ie, the DIY ECU software is automated, it seems to work fine.

Thanks.