Bugfix text display in update mode (flipped display) and reduction of timeout in case of a failed firmware update The text shown during firmware update was not shown in the correct position => updated screen orientation In case of an interrupt of a firmware update the sw was froozen for about 60 seconds (former timeout for receiption of data block). To reduce the timeout to 6 seconds the receiption of date will now be split into blocks of 16k byte instead of 64k byte.

Imported from Ac6/SystemWorkbench/plugins/fr.ac6.mcu.firmware_1.14.7.201711101414/resources/builtin/:
* File syscalls.c