Thanks for answer.
Yep, I installed standard image.
Since I was using two storage devices (SD and MMC), I first noticed issues with the mounted file system on the SD card, which I eventually had to remove (only the MMC storage remained). Then I noticed errors causing the processor to freeze, which got me a little worried.
It was long time ago when last time I was compiling Linux kernel (FreeBSD more recently) , but maybe I will try to follow your instructions and try to do it.
Many Thanks