It says on the OSM wiki that Navilock NL-402U (which contains LEA-5H module) can be used with RTKlib with the right ROM installed. It was a surprise when I saw it, as I was planning on buying another receiver that can work with RTKlib. I’ve tried with u-blox’s latest firmware, but it seems required settings don’t show up as enabled in u-center. So…the “EXT” on the wiki is probably an unofficial firmware…

So far, no luck.