ERDAS IMAGINE gives error message : "eimg_FileOpen failed (33:Unsupported Raster format or non-Raster format)" while opening the *.raw or the associated *.hdr files.
The same files can be opened in ArcGIS.
The image files are single-band, 16-bit unsigned, little endian byte order, 754x480 RAW image files
If you review the following ERDAS IMAGINE documentation for the Raw File Format and compare it to the .raw file provided by the customer, you will notice that they are very different.
Raw File Format documention can be found at : https://hexagongeospatial.fluidtopics.net/reader/5VsIDRDWkTIfq4xcVz8V4w/PD1pRucvsL6ZwRHnMg9xSA
But it appears that those files mentioned in the customer's data, are in fact valid ENVI .hdr files. After comparing them to other known ENVI .hdr files, we found that if you remove the .raw filename extension from the RAW file in the data folder and select the .hdr file in the Select Layer To Add dialog IMAGINE will recognize the data.