gdalwarp -srcnodata 255 -dstalpha ... # completely transparent. See no image
gdalwarp -srcnodata 0 -dstalpha  ... # completely transparent. See no image
gdalwarp -srcnodata 255 ... # has no effect
gdalwarp -srcnodata 0 ... # also has no effect

gdal_translate -of VRT 1-A.tif color.vrt

....
<VRTRasterBand dataType="Byte" band="1">
<Metadata domain="IMAGE_STRUCTURE">
  <MDI key="NBITS">1</MDI>
</Metadata>
<NoDataValue>255</NoDataValue>
<ColorInterp>Palette</ColorInterp>
<ColorTable>
  <Entry c1="255" c2="255" c3="255" c4="255" />
  <Entry c1="0" c2="0" c3="0" c4="255" />
</ColorTable>
<SimpleSource>
  <SourceFilename relativeToVRT="1">1-A.tif</SourceFilename>
  <SourceBand>1</SourceBand>
  <SourceProperties RasterXSize="5990" RasterYSize="5995" DataType="Byte" BlockXSize="5990" BlockYSize="10" />
  <SrcRect xOff="0" yOff="0" xSize="5990" ySize="5995" />
  <DstRect xOff="0" yOff="0" xSize="5990" ySize="5995" />
</SimpleSource>