modified to update the external flash memory on Einsy boards.
Due to a bug in the USB to serial converter firmware on the Prusa Einsy
boards, the STK500 protocol has been modified to never send semicolon
characters towards the main processor.
This firmware updater is compatible with a modified avrdude using
the "arduino" protocol, see the following commit.
https://github.com/prusa3d/Slic3r/tree/fwupdater_languages
printf float library enabled - platform.txt must be modified!
+flash usage optimalization - printing to serial line
current flash usage: 253206bytes (MK3 + ML support)
platform.txt original line 20:
compiler.c.elf.flags=-w -Os -Wl,--gc-sections
platform.txt modified line 20 (enable printf float library)
compiler.c.elf.flags=-w -Os -Wl,-u,vfprintf -lprintf_flt -lm -Wl,--gc-sections
Again another fix from https://github.com/prusa3d/Prusa-Firmware/pull/138 made by @Thess for the MK2 branch which i think is quite important.
Ardunio IDE 1.8.5 result with Compiler warnings set to "More" or "All"
```
sketch\Marlin_main.cpp:3265:44: warning: the address of 'retracted' will always evaluate as 'true' [-Waddress]
if((echange<-MIN_RETRACT && !retracted) || (echange>MIN_RETRACT && retracted)) { //move appears to be an attempt to retract or recover
^
sketch\Marlin_main.cpp:3265:82: warning: the address of 'retracted' will always evaluate as 'true' [-Waddress]
if((echange<-MIN_RETRACT && !retracted) || (echange>MIN_RETRACT && retracted)) { //move appears to be an attempt to retract or recover
^
sketch\Marlin_main.cpp:3268:28: warning: the address of 'retracted' will always evaluate as 'true' [-Waddress]
retract(!retracted);
^
sketch\Marlin_main.cpp:3870:15: warning: statement has no effect [-Wunused-value]
```
I don't know if that helps making small pull requests as they are easier to review or it would make sense to combine few more.
Prusa should really review this pull [request](https://github.com/prusa3d/Prusa-Firmware/pull/138) again for the MK3 branch, as it was one that made warnings disapear in the MK2 branch and made finding new flaws in the code much much easier.
