compared to the STM32F1, the STM32F4 does not used 1 KB flash pages.
F4 uses variable large (>= 16 KB) flash sections.
this makes using the last page (128 KB instead of 1KB) for EEPROM highly inefficient.
caching such large pages before reprogramming small portion is also no doable (there is not enough RAM).
thus almost all F1 utilities are not applicable anymore.
to help erasing the right section, a utility to get the section from an address is added.