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1) Get the HGT files and create contour lines to import to OSM:
    phyghtmap --pbf --srtm=1 --a -43.7544:-23.2363:-42.0378:-22.3183 --earthdata-user=myuser --earthdata-password=mypassword

2) Create VRT from the HGT files:
    gdalbuildvrt ./teste.vrt hgt/SRTM1v3.0/S23W043.hgt  hgt/SRTM1v3.0/S23W044.hgt  hgt/SRTM1v3.0/S24W043.hgt  hgt/SRTM1v3.0/S24W044.hgt

3) Do the abracadabra: 
    gdal_translate -tr 0.000050 0.000050 -r cubicspline -of GTiff test.vrt test.tif

4) And now do some kunk-fu:
    gdaldem hillshade -co TILED=YES -co compress=lzw -s 111120 -z 5 -combined -compute_edges test.tif final.tif

5) Import contour lines to OSM. I prefer to create a separate database and give a small `.style` to import just the needed columns.
    osm2pgsql --verbose --create --style ./srtm.style --database contour --username postgres -W --host 127.0.0.1 lon-43.23_-43.05lat-23.00_-22.90_srtm1v3.0.osm.pbf
    osm2pgsql --verbose --append <all other pbf files> (be careful with --append parameter) 

1) Get the HGT files and create contour lines to import to OSM:
    phyghtmap --pbf --srtm=1 --a -43.7544:-23.2363:-42.0378:-22.3183 --earthdata-user=myuser --earthdata-password=mypassword

2) Create VRT from the HGT files:
    gdalbuildvrt ./teste.vrt hgt/SRTM1v3.0/S23W043.hgt  hgt/SRTM1v3.0/S23W044.hgt  hgt/SRTM1v3.0/S24W043.hgt  hgt/SRTM1v3.0/S24W044.hgt

3) Do the abracadabra: 
    gdal_translate -tr 0.000050 0.000050 -r cubicspline -of GTiff test.vrt test.tif

4) And now do some kung-fu-code:
    gdaldem hillshade -co TILED=YES -co compress=lzw -s 111120 -z 5 -combined -compute_edges test.tif final.tif

5) Import contour lines to OSM. I prefer to create a separate database and give a small `.style` to import just the needed columns.
    osm2pgsql --verbose --create --style ./srtm.style --database contour --username postgres -W --host 127.0.0.1 lon-43.23_-43.05lat-23.00_-22.90_srtm1v3.0.osm.pbf
    osm2pgsql --verbose --append <all other pbf files> (be careful with --append parameter)