I am very curious what goes into adding a new board to the "duino" IDE. I noticed how there are several toolchains you can install integrated in the IDE.
I am working congruently on several projects but if anyone is still interested in this I will build hardware and software support for it.
I am assuming I need to build a toolchain and cross compile some libraries. Nothing in life is ever so simple. But this is worth doing.
There are basically 3 toolchains
All of them use the Arduino IDE and GCC.
For F103 and partial support for the F4, there is the Libmaple based Arduino core (based on work by Leaflabs for their maple products and is a not based on the standard peripheral lib or cmsis etc etc) http://github.com/rogerclarkmelbourne/arduino_stm32
Avik De, has written Kodunio which is based on the old standard peripheral library / cmsis from STM http://github.com/avikde/koduino
More recently STM have written their own Arduino core for the F103 and L476 MCU's http://github.com/stm32duino
At the moment we don't have a simple way to support the F7 series boards. Either Koduino or the STM core are your best bet, and I suspect that the STM core will eventually replace Koduino - but Libmaple could exist for a lot longer as its lightweight and does not have any license restrictions so can be run on GD32 processors as well as STM32
STM will be releasing the F4 or F0 core next, (They have not told me which or whether they will release both together), but I think that porting of the F4 to F7 would be your simplest route