Trigger (NORM, SINGLE) doesn't work

[ai91]

HW: brand new DSO138 (most probably not original, but clone. based on assembly manual, it's a Rev.05, 13803k-13804k version). Without "trigger switch" modification, with encoder mod.
SW: DLO-138_encoder_1.0.bin, DLO-138_switches_1.0.bin, also compiled latest from sources.

Problem:
Neither trigger-LED, nor trigger event don't work.
When switching to NORM or SING mode, the "sampling..." message appears on screen, but never gets triggered.

When flashed stock firmware back, everything works as expected (LED flashes and trigger events happen).