Yeap, it works - I copied .rockbox folder from build I've made from actual Git source (with 4 mb memory; 8 and 16 mb show white screen after Rockbox logo) on SD card and put there BASE.RKW from your working build. Now, when I'm checking Rockbox Info, it shows "b57536db8dM-240409". I guess, it should mean that software involved in playing is also updated.
Thanks a lot again!