diff --git a/tests/data_files/Makefile b/tests/data_files/Makefile
index 9df46aa59a..80bdd25737 100644
--- a/tests/data_files/Makefile
+++ b/tests/data_files/Makefile
@@ -1387,33 +1387,33 @@ all_final += pkcs7_signerInfo_2_invalid_tag.der
 # pkcs7 signature file with corrupted signer info[1]
 pkcs7_data_signed_badsigner1_badsize.der: pkcs7_data_3_signed.der
 	cp pkcs7_data_3_signed.der $@
-	echo '\x72' | xxd -p -r | dd of=$@ bs=1 seek=438 conv=notrunc
+	echo '72' | xxd -p -r | dd of=$@ bs=1 seek=438 conv=notrunc
 all_final += pkcs7_data_signed_badsigner1_badsize.der
 
 pkcs7_data_signed_badsigner1_badtag.der: pkcs7_data_3_signed.der
 	cp pkcs7_data_3_signed.der $@
-	echo '\xa1' | xxd -p -r | dd of=$@ bs=1 seek=442 conv=notrunc
+	echo 'a1' | xxd -p -r | dd of=$@ bs=1 seek=442 conv=notrunc
 all_final += pkcs7_data_signed_badsigner1_badtag.der
 
 pkcs7_data_signed_badsigner1_fuzzbad.der: pkcs7_data_3_signed.der
 	cp pkcs7_data_3_signed.der $@
-	echo '\xa1' | xxd -p -r | dd of=$@ bs=1 seek=550 conv=notrunc
+	echo 'a1' | xxd -p -r | dd of=$@ bs=1 seek=550 conv=notrunc
 all_final += pkcs7_data_signed_badsigner1_fuzzbad.der
 
 # pkcs7 signature file with corrupted signer info[2]
 pkcs7_data_signed_badsigner2_badsize.der: pkcs7_data_3_signed.der
 	cp pkcs7_data_3_signed.der $@
-	echo '\x72'| xxd -p -r | dd of=$@ bs=1 seek=813 conv=notrunc
+	echo '72'| xxd -p -r | dd of=$@ bs=1 seek=813 conv=notrunc
 all_final += pkcs7_data_signed_badsigner2_badsize
 
 pkcs7_data_signed_badsigner2_badtag.der: pkcs7_data_3_signed.der
 	cp pkcs7_data_3_signed.der $@
-	echo '\xa1'| xxd -p -r | dd of=$@ bs=1 seek=817 conv=notrunc
+	echo 'a1'| xxd -p -r | dd of=$@ bs=1 seek=817 conv=notrunc
 all_final += pkcs7_data_signed_badsigner2_badtag
 
 pkcs7_data_signed_badsigner2_fuzzbad.der: pkcs7_data_3_signed.der
 	cp pkcs7_data_3_signed.der $@
-	echo '\xa1'| xxd -p -r | dd of=$@ bs=1 seek=925 conv=notrunc
+	echo 'a1'| xxd -p -r | dd of=$@ bs=1 seek=925 conv=notrunc
 all_final += pkcs7_data_signed_badsigner2_fuzzbad
 
 # pkcs7 file with version 2