executing code from SRAM

Hello,

i am using a Cortex M0 which has 24MhZ Flash and 48MhZ Core speed with await state in case Flash is too low.

I want to execute my ISR from SRAm to improve speed a bit.

In the scatter file i implemented the following:

SRAM_Execution 0x20001000 0x1000 { stm32f0xx_isr.o
}

When i click on compile the map file says that the functions are placed in SRAM. Also som Vemeers are added.

Unfortunately the machine does not work when adding this to the scatter file

What am i missing?
I though that the call of main() will copy the functions from Flash to SRAM before starting the application.