setFontCustom bitmap format vs vertical_byte:true - GT24L24A2Y fontchip in F07 fitness tracker

got it working, last catch was lsb to msb conversion (did via table, named M2L in code below)

function createFont(off,bs,w,h,c,isprop){
  var ptr=0x60000000+off;
  var f=require("Flash");
  var hbytes=h>>3;
  var bmp=new Uint8Array(w*hbytes*c);
  var widths=isprop ? Uint8Array(c) : w;
  var bmpidx=0;
  for (var i=0;i<c;i++){
    var buff=f.read(bs,ptr+i*bs);
    var wprop=w;
    if (isprop){wprop=1+buff[0];widths[i]=wprop;buff[0]=0;}
    var x,y;bi=0;
    for(y=0;y<hbytes;y++){
      for(x=0;x<wprop;x++)
        bmp[bmpidx+x*hbytes+y]=M2L[buff[bi+x]];
      bi+=w;
    }
    bmpidx+=wprop*hbytes;
    E.kickWatchdog();
  }
  if (isprop){
    return { font: E.toString(Uint8Array(bmp.buffer,0,bmpidx)), widths: E.toString(widths)};
  }
  return { font: E.toString(bmp), widths: w};
}

then to set font https://github.com/RichardBsolut/GT24L24A2Y#font-clock-2-34x48 I use it like

fnt=createFont(0x19de96,206,34,48,14,true)
g.setFontCustom(fnt.font,0x30,fnt.widths,48)

however the code is a bit slow for fonts with more characters so I need to ping the watchdog

and BTW found out that GT24L24A2Y is otherwise pretty normal 2MB SPI flash that I can write and erase and space over 0x1A3000 is empty so I could perhaps convert those fonts once and write back in better format to load them directly next time