GTA04 Block V4

[Werner Almesberger]

Ian Stirling wrote:
> I think you can always mass-erase the chip though, so a USB bootloader  
> would not survive malicious users.

It's even easier: according to the manual, you can simply turn off
the protection and then scribble over things, see [1].

> As I read it, some of the STM32 family tick most of these.

Yes, they look very very good. Their main problem is that they seem
brickable. This could be solved by booting from a serial flash
(STR750 family, [2]), but that would add yet another component,
which isn't desirable.

[1] "STR7 family Flash programming"
    http://www.st.com/stonline/books/pdf/docs/11130.pdf
    section 3.3.

[2] "STR750 ARM7TDMI-S-based microcontroller family Reference Manual"
    http://www.ftp2u.com/datasheet/str75xf_m.pdf
    sections 1.4 and 1.4.2.

Oh, and I forgot the most important requirement: fully documented
without silly restrictions :)

- Werner