diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/AmazonS3.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/AmazonS3.java
index 1e7f3b1f0..9210ec172 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/AmazonS3.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/AmazonS3.java
@@ -33,6 +33,7 @@
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Collections;
+import java.util.Comparator;
 import java.util.Date;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -44,6 +45,8 @@
 import java.util.SortedMap;
 import java.util.TimeZone;
 import java.util.TreeMap;
+import java.util.stream.Collectors;
+import java.time.Instant;
 
 import javax.crypto.Mac;
 import javax.crypto.spec.SecretKeySpec;
@@ -288,6 +291,8 @@ public InputStream decrypt(URLConnection u) throws IOException {
 	 * <p>
 	 * This method is primarily meant for obtaining a "recursive directory
 	 * listing" rooted under the specified bucket and prefix location.
+	 * It returns the keys sorted in reverse order of LastModified time
+	 * (freshest keys first).
 	 *
 	 * @param bucket
 	 *            name of the bucket whose objects should be listed.
@@ -311,7 +316,10 @@ public List<String> list(String bucket, String prefix)
 		do {
 			lp.list();
 		} while (lp.truncated);
-		return lp.entries;
+
+		Comparator<KeyInfo> comparator = Comparator.comparingLong(KeyInfo::getLastModifiedSecs);
+		return lp.entries.stream().sorted(comparator.reversed())
+			.map(KeyInfo::getName).collect(Collectors.toList());
 	}
 
 	/**
@@ -620,8 +628,26 @@ static Properties properties(File authFile)
 		return p;
 	}
 
+	/**
+	 * KeyInfo enables sorting of keys by lastModified time
+	 */
+	private static final class KeyInfo {
+		private final String name;
+		private final long lastModifiedSecs;
+		public KeyInfo(String aname, long lsecs) {
+			name = aname;
+			lastModifiedSecs = lsecs;
+		}
+		public String getName() {
+			return name;
+		}
+		public long getLastModifiedSecs() {
+			return lastModifiedSecs;
+		}
+	}
+
 	private final class ListParser extends DefaultHandler {
-		final List<String> entries = new ArrayList<>();
+		final List<KeyInfo> entries = new ArrayList<>();
 
 		private final String bucket;
 
@@ -630,6 +656,8 @@ private final class ListParser extends DefaultHandler {
 		boolean truncated;
 
 		private StringBuilder data;
+		private String keyName;
+		private Instant keyLastModified;
 
 		ListParser(String bn, String p) {
 			bucket = bn;
@@ -641,7 +669,7 @@ void list() throws IOException {
 			if (prefix.length() > 0)
 				args.put("prefix", prefix); //$NON-NLS-1$
 			if (!entries.isEmpty())
-				args.put("marker", prefix + entries.get(entries.size() - 1)); //$NON-NLS-1$
+				args.put("marker", prefix + entries.get(entries.size() - 1).getName()); //$NON-NLS-1$
 
 			for (int curAttempt = 0; curAttempt < maxAttempts; curAttempt++) {
 				final HttpURLConnection c = open("GET", bucket, "", args); //$NON-NLS-1$ //$NON-NLS-2$
@@ -650,6 +678,8 @@ void list() throws IOException {
 				case HttpURLConnection.HTTP_OK:
 					truncated = false;
 					data = null;
+					keyName = null;
+					keyLastModified = null;
 
 					final XMLReader xr;
 					try {
@@ -683,8 +713,13 @@ void list() throws IOException {
 		public void startElement(final String uri, final String name,
 				final String qName, final Attributes attributes)
 				throws SAXException {
-			if ("Key".equals(name) || "IsTruncated".equals(name)) //$NON-NLS-1$ //$NON-NLS-2$
+			if ("Key".equals(name) || "IsTruncated".equals(name) || "LastModified".equals(name)) { //$NON-NLS-1$ //$NON-NLS-2$ //$NON-NLS-3$
 				data = new StringBuilder();
+			}
+			if ("Contents".equals(name)) { //$NON-NLS-1$
+				keyName = null;
+				keyLastModified = null;
+			}
 		}
 
 		@Override
@@ -704,10 +739,16 @@ public void characters(char[] ch, int s, int n)
 		@Override
 		public void endElement(final String uri, final String name,
 				final String qName) throws SAXException {
-			if ("Key".equals(name)) //$NON-NLS-1$
-				entries.add(data.toString().substring(prefix.length()));
-			else if ("IsTruncated".equals(name)) //$NON-NLS-1$
+			if ("Key".equals(name))  { //$NON-NLS-1$
+				keyName = data.toString().substring(prefix.length());
+			} else if ("IsTruncated".equals(name)) { //$NON-NLS-1$
 				truncated = StringUtils.equalsIgnoreCase("true", data.toString()); //$NON-NLS-1$
+			} else if ("LastModified".equals(name)) { //$NON-NLS-1$
+				keyLastModified = Instant.parse(data.toString());
+			} else if ("Contents".equals(name)) { //$NON-NLS-1$
+				entries.add(new KeyInfo(keyName, keyLastModified.getEpochSecond()));
+			}
+
 			data = null;
 		}
 	}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransportAmazonS3.java b/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransportAmazonS3.java
index 94f36d285..784f56615 100644
--- a/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransportAmazonS3.java
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/transport/TransportAmazonS3.java
@@ -23,6 +23,7 @@
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Properties;
 import java.util.Set;
@@ -241,11 +242,14 @@ WalkRemoteObjectDatabase openAlternate(String location)
 
 		@Override
 		Collection<String> getPackNames() throws IOException {
+			// s3.list returns most recently modified packs first.
+			// These are the packs most likely to contain missing refs.
+			final List<String> packList = s3.list(bucket, resolveKey("pack")); //$NON-NLS-1$
 			final HashSet<String> have = new HashSet<>();
-			have.addAll(s3.list(bucket, resolveKey("pack"))); //$NON-NLS-1$
+			have.addAll(packList);
 
 			final Collection<String> packs = new ArrayList<>();
-			for (String n : have) {
+			for (String n : packList) {
 				if (!n.startsWith("pack-") || !n.endsWith(".pack")) //$NON-NLS-1$ //$NON-NLS-2$
 					continue;