diff --git a/CMakeLists.txt b/CMakeLists.txt
index 3168da78..837e39df 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -357,8 +357,15 @@ if (nexus)
     endif()
 
     #--- try to extract the HDF4 version from H4config.h (autotools builds) --------
+    # Some distributions (e.g. Debian/Ubuntu's libhdf4-dev) install it lower-cased
+    # as 'h4config.h' instead of the upstream 'H4config.h', so check both.
     if (EXISTS "${HDF4_INCLUDE_DIR}/H4config.h")
-      file(STRINGS "${HDF4_INCLUDE_DIR}/H4config.h" HDF4_VERSION_LINE REGEX "^#define[ \t]+H4_VERSION[ \t]+\"[^\"]*\"")
+      set(HDF4_CONFIG_HEADER "${HDF4_INCLUDE_DIR}/H4config.h")
+    elseif (EXISTS "${HDF4_INCLUDE_DIR}/h4config.h")
+      set(HDF4_CONFIG_HEADER "${HDF4_INCLUDE_DIR}/h4config.h")
+    endif ()
+    if (HDF4_CONFIG_HEADER)
+      file(STRINGS "${HDF4_CONFIG_HEADER}" HDF4_VERSION_LINE REGEX "^#define[ \t]+H4_VERSION[ \t]+\"[^\"]*\"")
       string(REGEX REPLACE "^#define[ \t]+H4_VERSION[ \t]+\"([^\"]*)\".*" "\\1" HDF4_VERSION "${HDF4_VERSION_LINE}")
     endif ()