Bootloader jump to application

[ABOSTM]

Summary
After UART Bootloader to jump to application, 2 issues prevent application to run properly:

• Bootloader changes VTOR register and did not restore it when jumping to application
  It is necessary that application set VTOR unconditionally

• Bootloader set PLL as SystemClock and keep it when jumping to application
  This prevent any further configuration of the PLL.
  It is necessary change SystemClock source, for example revert to default SystemClock (HSI or MSI) before any further PLL configuration.

Fixes #1637

[olikraus]

To me it looks like many system_xxx.c files are changed. Wouldn't it be better to set "-DUSER_VECT_TAB_ADDRESS" once in the plattform.txt file, for example here:

Arduino_Core_STM32/platform.txt

Line 31 in de25178

compiler.extra_flags=-mcpu={build.mcu} {build.flags.fp} -DUSE_FULL_LL_DRIVER -mthumb "@{build.opt.path}"

I see that the PLL is also changed, so I guess that additional change for the VTOR doesn't matter than and the plattform.txt change is not required.

Anyhow, thanks for adding this. It will simplify work for USART users :-)

[fpistm]

To me it looks like many system_xxx.c files are changed. Wouldn't it be better to set "-DUSER_VECT_TAB_ADDRESS" once in the plattform.txt file, for example here:

Arduino_Core_STM32/platform.txt

Line 31 in de25178

compiler.extra_flags=-mcpu={build.mcu} {build.flags.fp} -DUSE_FULL_LL_DRIVER -mthumb "@{build.opt.path}"

In fact, this was change by the STM32CubeFW to introduce the USER_VECT_TAB_ADDRESS and we simply aligned it but it brought a side effect with some BL modes. So easiest way is to remove it as it has no benefit.
Same for the clock reset config, before the system_init provided it but was removed.
Crosscheck with BL team brought us to simply restore VTOR and clock by default.

[ABOSTM]

I see that the PLL is also changed, so I guess that additional change for the VTOR doesn't matter than and the plattform.txt change is not required.

Both changes are required to guarantee proper application run, after UART Bootloader.