diff --git a/script/test-smoke.sh b/script/test-smoke.sh
index 2505ae38..b85d9ed5 100755
--- a/script/test-smoke.sh
+++ b/script/test-smoke.sh
@@ -116,21 +116,7 @@ if [ -z "$SKIP_DUCK" ]; then
   done
 fi
 
-rm /tmp/garage.{1..3}.{rnd,b64}
-
-if [ -z "$SKIP_AWS" ]; then
-  echo "🧪 Website Testing"
-  echo "<h1>hello world</h1>" > /tmp/garage-index.html
-  aws s3 cp /tmp/garage-index.html s3://eprouvette/index.html
-  [ `curl -s -o /dev/null -w "%{http_code}" --header "Host: eprouvette.garage.tld"  http://127.0.0.1:3921/ ` == 404 ]
-  garage -c /tmp/config.1.toml bucket website --allow eprouvette
-  [ `curl -s -o /dev/null -w "%{http_code}" --header "Host: eprouvette.garage.tld"  http://127.0.0.1:3921/ ` == 200 ]
-  garage -c /tmp/config.1.toml bucket website --deny eprouvette
-  [ `curl -s -o /dev/null -w "%{http_code}" --header "Host: eprouvette.garage.tld"  http://127.0.0.1:3921/ ` == 404 ]
-  aws s3 rm s3://eprouvette/index.html
-  rm /tmp/garage-index.html
-fi
-
+# Advanced testing via S3API
 if [ -z "$SKIP_AWS" ]; then
   echo "🔌 Test S3API"
 
@@ -265,8 +251,61 @@ if [ -z "$SKIP_AWS" ]; then
       aws s3api abort-multipart-upload --bucket eprouvette --key $key --upload-id $uid;
       echo "Deleted ${key}:${uid}"
     done
+
+  # Test for UploadPartCopy
+  aws s3 cp "/tmp/garage.3.rnd" "s3://eprouvette/copy_part_source"
+  UPLOAD_ID=$(aws s3api create-multipart-upload --bucket eprouvette --key test_multipart | jq -r .UploadId)
+  PART1=$(aws s3api upload-part \
+    --bucket eprouvette --key test_multipart \
+    --upload-id $UPLOAD_ID --part-number 1 \
+    --body /tmp/garage.2.rnd | jq .ETag)
+  PART2=$(aws s3api upload-part-copy \
+    --bucket eprouvette --key test_multipart \
+    --upload-id $UPLOAD_ID --part-number 2 \
+    --copy-source "/eprouvette/copy_part_source" \
+    --copy-source-range "bytes=500-5000500" \
+    | jq .CopyPartResult.ETag)
+  PART3=$(aws s3api upload-part \
+    --bucket eprouvette --key test_multipart \
+    --upload-id $UPLOAD_ID --part-number 3 \
+    --body /tmp/garage.3.rnd | jq .ETag)
+  cat >/tmp/garage.multipart_struct <<EOF
+{
+  "Parts": [
+    {
+      "ETag": $PART1,
+      "PartNumber": 1
+    },
+    {
+      "ETag": $PART2,
+      "PartNumber": 2
+    },
+    {
+      "ETag": $PART3,
+      "PartNumber": 3
+    }
+  ]
+}
+EOF
+  aws s3api complete-multipart-upload \
+    --bucket eprouvette --key test_multipart --upload-id $UPLOAD_ID \
+    --multipart-upload file:///tmp/garage.multipart_struct
+
+  aws s3 cp "s3://eprouvette/test_multipart" /tmp/garage.test_multipart
+  cat /tmp/garage.2.rnd <(tail -c +501 /tmp/garage.3.rnd | head -c 5000001) /tmp/garage.3.rnd > /tmp/garage.test_multipart_reference
+  diff /tmp/garage.test_multipart /tmp/garage.test_multipart_reference >/tmp/garage.test_multipart_diff 2>&1
+
+  aws s3 rm "s3://eprouvette/copy_part_source"
+  aws s3 rm "s3://eprouvette/test_multipart"
+
+  rm /tmp/garage.multipart_struct
+  rm /tmp/garage.test_multipart
+  rm /tmp/garage.test_multipart_reference
+  rm /tmp/garage.test_multipart_diff
 fi
 
+rm /tmp/garage.{1..3}.{rnd,b64}
+
 if [ -z "$SKIP_AWS" ]; then
   echo "🪣 Test bucket logic "
   AWS_ACCESS_KEY_ID=`cat /tmp/garage.s3 |cut -d' ' -f1`
@@ -282,6 +321,19 @@ if [ -z "$SKIP_AWS" ]; then
   [ $(aws s3 ls | wc -l) == 1 ]
 fi
 
+if [ -z "$SKIP_AWS" ]; then
+  echo "🧪 Website Testing"
+  echo "<h1>hello world</h1>" > /tmp/garage-index.html
+  aws s3 cp /tmp/garage-index.html s3://eprouvette/index.html
+  [ `curl -s -o /dev/null -w "%{http_code}" --header "Host: eprouvette.garage.tld"  http://127.0.0.1:3921/ ` == 404 ]
+  garage -c /tmp/config.1.toml bucket website --allow eprouvette
+  [ `curl -s -o /dev/null -w "%{http_code}" --header "Host: eprouvette.garage.tld"  http://127.0.0.1:3921/ ` == 200 ]
+  garage -c /tmp/config.1.toml bucket website --deny eprouvette
+  [ `curl -s -o /dev/null -w "%{http_code}" --header "Host: eprouvette.garage.tld"  http://127.0.0.1:3921/ ` == 404 ]
+  aws s3 rm s3://eprouvette/index.html
+  rm /tmp/garage-index.html
+fi
+
 echo "🏁 Teardown"
 AWS_ACCESS_KEY_ID=`cat /tmp/garage.s3 |cut -d' ' -f1`
 AWS_SECRET_ACCESS_KEY=`cat /tmp/garage.s3 |cut -d' ' -f2`
diff --git a/src/api/s3_copy.rs b/src/api/s3_copy.rs
index c37bb138..7e91ecd8 100644
--- a/src/api/s3_copy.rs
+++ b/src/api/s3_copy.rs
@@ -537,6 +537,7 @@ impl CopyPreconditionHeaders {
 			}
 			(None, None, Some(inm), None) => !inm.iter().any(|x| x == etag || x == "*"),
 			(None, None, None, Some(ims)) => v_date > *ims,
+			(None, None, None, None) => true,
 			_ => {
 				return Err(Error::BadRequest(
 					"Invalid combination of x-amz-copy-source-if-xxxxx headers".into(),
diff --git a/src/api/signature.rs b/src/api/signature.rs
index c580cb3a..311e6a9a 100644
--- a/src/api/signature.rs
+++ b/src/api/signature.rs
@@ -266,10 +266,13 @@ fn canonical_header_string(headers: &HashMap<String, String>, signed_headers: &s
 	let mut items = headers
 		.iter()
 		.filter(|(key, _)| signed_headers_vec.contains(&key.as_str()))
-		.map(|(key, value)| key.to_lowercase() + ":" + value.trim())
 		.collect::<Vec<_>>();
-	items.sort();
-	items.join("\n")
+	items.sort_by(|(k1, _), (k2, _)| k1.cmp(k2));
+	items
+		.iter()
+		.map(|(key, value)| key.to_lowercase() + ":" + value.trim())
+		.collect::<Vec<_>>()
+		.join("\n")
 }
 
 fn canonical_query_string(uri: &hyper::Uri) -> String {