hi. I made 10 sample boards.
and 3 board are working strange.
I tested dfu bootloader in system memory with usb. (boot mode BOOT0 = 1)
7 boards are working fine with my firmware and bootloader.
buy 3 boards are working only with my firmware. it can not go into dfu mode.
I use 25Mhz Hse crystal. and my firmware use 168Mhz system clock and USB system work fine.
So I tried to find the problem and I found something strange thing.
I read mcu information from ST-Link Utility.
Normal(working fine) board shows correct information
my mcu is STM32F407IE that has 512KB flash memory . so captured screen(407normal) shows correct size.
but 407wrong file show flash size with unknown.
It seems like it has a 1MB flash.
and I tested read/write memory over 512KB space.
I got a error message from normal boards but three borads are working !
and the three board are now have a problem with DFU.
I used latest ST-Link Utility(4.3.0) and latest ST-LINK V2 firmware.
How can this happen?
please help me.
