userSP = _iocs_b_super(0); // enter supervisor mode
    _iocs_crtmod(0xA);      // 256x256 actual

    *CRTC_R20 = 0x1110;
    *VIDCON_R0 = 1;         // 512x512 8-bit GVRAM
    *VIDCON_R2 = 0x0;       // no display
    *VIDCON_R1 = 0x6E4;     // prio: bg/sprite, text, graphic - gv0/1, gv2/3
    *BG_CONTROL = 0x219;    // display BG0


    StartVsync();
    *VIDCON_R2 = 0x144F;     // all GVRAM display. bit 10 (B/P) must be set to
                            // enable the 'i' bit for 'special priority'
    iocs_b_super(userSP);