It will doing mass erase or only erase the part will using when use ST-LINK Utility program MCUs ?

[SAS.1]

For some reason , some of my products will be updated by using ST-link with ST-LINK Utility .

The MCU I used is STM32L031K6T6 , it have 32KBytes flash rom .The program I writed total ROM size is 30488 ( 29.77kB) , in ST-LINK utility it said my program address range is from 0x0800 0000 to 0x0800 7718 .

I save some information at the end of the flash , address at 0x0800 7f00 .

So now I test on my side , usually after PROGRAMMING , my information at 0x0800 7f00 not be erase .

But I am not sure how the ST-LINK utility doing erase flash before programing . Dose it alwasys just erase the sector which the hex file will used ?

[MM..1]

Based on config in IDE or prog, both is possible.