diff --git a/diff.c b/diff.c
index 0a43869435..5422c43882 100644
--- a/diff.c
+++ b/diff.c
@@ -4412,7 +4412,7 @@ size_t fill_textconv(struct userdiff_driver *driver,
 		return df->size;
 	}
 
-	if (driver->textconv_cache) {
+	if (driver->textconv_cache && df->sha1_valid) {
 		*outbuf = notes_cache_get(driver->textconv_cache, df->sha1,
 					  &size);
 		if (*outbuf)
@@ -4423,7 +4423,7 @@ size_t fill_textconv(struct userdiff_driver *driver,
 	if (!*outbuf)
 		die("unable to read files to diff");
 
-	if (driver->textconv_cache) {
+	if (driver->textconv_cache && df->sha1_valid) {
 		/* ignore errors, as we might be in a readonly repository */
 		notes_cache_put(driver->textconv_cache, df->sha1, *outbuf,
 				size);
diff --git a/t/t8006-blame-textconv.sh b/t/t8006-blame-textconv.sh
index dbf623bce5..ea64cd8d0f 100755
--- a/t/t8006-blame-textconv.sh
+++ b/t/t8006-blame-textconv.sh
@@ -73,6 +73,27 @@ test_expect_success 'blame --textconv going through revisions' '
 	test_cmp expected result
 '
 
+test_expect_success 'setup +cachetextconv' '
+	git config diff.test.cachetextconv true
+'
+
+cat >expected_one <<EOF
+(Number2 2010-01-01 20:00:00 +0000 1) converted: test 1 version 2
+EOF
+
+test_expect_success 'blame --textconv works with textconvcache' '
+	git blame --textconv two.bin >blame &&
+	find_blame <blame >result &&
+	test_cmp expected result &&
+	git blame --textconv one.bin >blame &&
+	find_blame  <blame >result &&
+	test_cmp expected_one result
+'
+
+test_expect_success 'setup -cachetextconv' '
+	git config diff.test.cachetextconv false
+'
+
 test_expect_success 'make a new commit' '
 	echo "bin: test number 2 version 3" >>two.bin &&
 	GIT_AUTHOR_NAME=Number3 git commit -a -m Third --date="2010-01-01 22:00:00"