diff --git a/metis_l1_prep.pro b/metis_l1_prep.pro
index 367201950e1c04804714d2ed0b0179f7443f9968..3742f4915f226710d3ad4e2b0b548778f94a27a3 100755
--- a/metis_l1_prep.pro
+++ b/metis_l1_prep.pro
@@ -488,7 +488,7 @@ pro metis_l1_prep
 	; if applicable, save the data binary-table extension as it is
 
 	if isa(data_bin_table) then begin
-		fits_add_checksum, data_extension_header, data_bin_table
+		if datatype lt 9 then fits_add_checksum, data_extension_header, data_bin_table
 		mwrfits, data_bin_table, out_file_name, data_extension_header, /no_comment, /silent
 	endif