Different behaviour between linux and embedded implementation

[tescik]

But still the question remains: why it works in one env. but not in the other........
How can I find/narrow down the origin of this behaviour?

[wysota]

But still the question remains: why it works in one env. but not in the other........
How can I find/narrow down the origin of this behaviour?

Probably Qt5 contains some fix or behavior change related to threads and signal handling which isn't present in Qt 4.