diff --git a/fips-check.sh b/fips-check.sh
index 7d0e588998..1e12de3afd 100755
--- a/fips-check.sh
+++ b/fips-check.sh
@@ -14,13 +14,18 @@
 MAKE="${MAKE:-make}"
 GIT="${GIT:-git -c advice.detachedHead=false}"
 TEST_DIR="${TEST_DIR:-XXX-fips-test}"
+case "$TEST_DIR" in
+    /*) ;;
+    *) TEST_DIR="${PWD}/${TEST_DIR}"
+       ;;
+esac
 FLAVOR="${FLAVOR:-linux}"
 KEEP="${KEEP:-no}"
 MAKECHECK=${MAKECHECK:-yes}
 DOCONFIGURE=${DOCONFIGURE:-yes}
 DOAUTOGEN=${DOAUTOGEN:-yes}
 FIPS_REPO="${FIPS_REPO:-git@github.com:wolfssl/fips.git}"
-WOLFSSL_REPO="${WOLFSSL_REPO:-origin}"
+WOLFSSL_REPO="${WOLFSSL_REPO:-git@github.com:wolfssl/wolfssl.git}"
 
 Usage() {
     cat <<usageText
@@ -435,51 +440,120 @@ function copy_fips_files() {
     done
 }
 
-declare -A FIPS_TAGS_NEEDED WOLFCRYPT_TAGS_NEEDED
-for file_entry in "${WOLFCRYPT_FILES[@]}"; do
-    WOLFCRYPT_TAGS_NEEDED["${file_entry#*:}"]=1
-done
-for file_entry in "${FIPS_FILES[@]}"; do
-    FIPS_TAGS_NEEDED["${file_entry#*:}"]=1
-done
+# Note, it would be cleaner to compute the tag lists using associative arrays,
+# but those were introduced in bash-4.  It's more important to maintain backward
+# compatibility here.
 
-echo "wolfCrypt tag$( [[ ${#WOLFCRYPT_TAGS_NEEDED[@]} != "1" ]] && echo -n 's'):"
-for tag in "${!WOLFCRYPT_TAGS_NEEDED[@]}"; do
-    if $GIT describe --exact-match --long "$tag" 2>/dev/null; then
-        continue
-    fi
-    if ! $GIT fetch --depth 1 "$WOLFSSL_REPO" tag "$tag"; then
-        echo "Can't fetch wolfCrypt tag: $tag"
+declare -a WOLFCRYPT_TAGS_NEEDED_UNSORTED WOLFCRYPT_TAGS_NEEDED
+if [ ${#WOLFCRYPT_FILES[@]} -gt 0 ]; then
+    for file_entry in "${WOLFCRYPT_FILES[@]}"; do
+        WOLFCRYPT_TAGS_NEEDED_UNSORTED+=("${file_entry#*:}")
+    done
+    while IFS= read -r tag; do WOLFCRYPT_TAGS_NEEDED+=("$tag"); done < <(IFS=$'\n'; sort -u <<< "${WOLFCRYPT_TAGS_NEEDED_UNSORTED[*]}")
+    if [ "${#WOLFCRYPT_TAGS_NEEDED[@]}" = "0" ]; then
+        echo "Error -- missing wolfCrypt tags." 1>&2
         exit 1
     fi
-done
+fi
 
-if ! $GIT clone . "$TEST_DIR"; then
-    echo "fips-check: Couldn't duplicate current working directory."
+declare -a FIPS_TAGS_NEEDED_UNSORTED FIPS_TAGS_NEEDED
+for file_entry in "${FIPS_FILES[@]}"; do
+    FIPS_TAGS_NEEDED_UNSORTED+=("${file_entry#*:}")
+done
+while IFS= read -r tag; do FIPS_TAGS_NEEDED+=("$tag"); done < <(IFS=$'\n'; sort -u <<< "${FIPS_TAGS_NEEDED_UNSORTED[*]}")
+if [ "${#FIPS_TAGS_NEEDED[@]}" = "0" ]; then
+    echo "Error -- missing FIPS tags." 1>&2
     exit 1
 fi
 
-pushd "$TEST_DIR" 1>/dev/null || exit 2
+if [ ${#WOLFCRYPT_TAGS_NEEDED[@]} -gt 0 ]; then
+    echo "wolfCrypt tag$( [[ ${#WOLFCRYPT_TAGS_NEEDED[@]} != "1" ]] && echo -n 's'):"
+
+    # Only use shallow fetch if the repo already has shallow branches, to avoid
+    # tainting full repos with shallow objects.
+    if [ -f .git/shallow ]; then
+        shallow_args=(--depth 1)
+    else
+        shallow_args=()
+    fi
+
+    for tag in "${WOLFCRYPT_TAGS_NEEDED[@]}"; do
+        if $GIT describe --long --exact-match "$tag" 2>/dev/null; then
+            continue
+        fi
+        if ! $GIT fetch "${shallow_args[@]}" "$WOLFSSL_REPO" tag "$tag"; then
+            echo "Can't fetch wolfCrypt tag: $tag" 1>&2
+            exit 1
+        fi
+    done
+fi
 
-if ! $GIT clone "$FIPS_REPO" fips; then
-    echo "fips-check: Couldn't check out FIPS repository."
+if ! $GIT clone --shared . "$TEST_DIR"; then
+    echo "fips-check: Couldn't clone current working directory." 1>&2
     exit 1
 fi
 
-pushd fips 1>/dev/null || exit 2
+# If there is a FIPS repo under the parent directory, leverage that:
+if [ -d ../fips/.git ]; then
+    pushd ../fips 1>/dev/null || exit 2
 
-echo "FIPS tag$( [[ ${#FIPS_TAGS_NEEDED[@]} != "1" ]] && echo -n 's'):"
-for tag in "${!FIPS_TAGS_NEEDED[@]}"; do
-    if $GIT describe "$tag" 2>/dev/null; then
-        continue
+    # Only use shallow fetch if the repo already has shallow branches, to avoid
+    # tainting full repos with shallow objects.
+    if [ -f .git/shallow ]; then
+        shallow_args=(--depth 1)
+    else
+        shallow_args=()
     fi
-    if ! $GIT fetch --depth 1 "$FIPS_REPO" tag "$tag"; then
-        echo "Can't fetch FIPS tag: $tag"
+
+    echo "FIPS tag$( [[ ${#FIPS_TAGS_NEEDED[@]} != "1" ]] && echo -n 's'):"
+    for tag in "${FIPS_TAGS_NEEDED[@]}"; do
+        # This may be a branch (master), not a tag, so we can't use
+        # --exact-match here.
+        if $GIT describe --long "$tag" 2>/dev/null; then
+            continue
+        fi
+        # Similarly, we can't limit the fetch to a "tag" here.
+        if ! $GIT fetch "${shallow_args[@]}" "$FIPS_REPO" "$tag"; then
+            echo "Can't fetch FIPS tag: $tag" 1>&2
+            exit 1
+        fi
+    done
+
+    if ! $GIT clone --shared --no-checkout . "${TEST_DIR}/fips"; then
+        echo "fips-check: Couldn't clone current working directory." 1>&2
         exit 1
     fi
-done
 
-popd 1>/dev/null || exit 2
+    FIPS_TAGS_CACHED_LOCALLY=y
+
+    popd 1>/dev/null || exit 2
+fi
+
+pushd "$TEST_DIR" 1>/dev/null || exit 2
+
+if [ ! -d fips ]; then
+    if ! $GIT clone --depth 1 --branch "${FIPS_TAGS_NEEDED[0]}" "$FIPS_REPO" fips; then
+        echo "fips-check: Couldn't check out FIPS repository."
+        exit 1
+    fi
+fi
+
+if [ "$FIPS_TAGS_CACHED_LOCALLY" != "y" ]; then
+    pushd fips 1>/dev/null || exit 2
+    echo "FIPS tag$( [[ ${#FIPS_TAGS_NEEDED[@]} != "1" ]] && echo -n 's'):"
+    for tag in "${FIPS_TAGS_NEEDED[@]}"; do
+        if $GIT describe --long "$tag" 2>/dev/null; then
+            continue
+        fi
+        # The FIPS repo here is an ephemeral clone, so we can safely use shallow
+        # fetch unconditionally.
+        if ! $GIT fetch --depth 1 "$FIPS_REPO" tag "$tag"; then
+            echo "Can't fetch FIPS tag: $tag" 1>&2
+            exit 1
+        fi
+    done
+    popd 1>/dev/null || exit 2
+fi
 
 checkout_files "${WOLFCRYPT_FILES[@]}" || exit 3
 pushd fips 1>/dev/null || exit 2