diff --git a/pkgs/build-support/fetchbzr/builder.sh b/pkgs/build-support/fetchbzr/builder.sh
index 88aab7891b4..17567fdadd2 100644
--- a/pkgs/build-support/fetchbzr/builder.sh
+++ b/pkgs/build-support/fetchbzr/builder.sh
@@ -4,6 +4,6 @@ header "exporting \`$url' (revision $revision) into \`$out'"
 
 # Perform a lightweight checkout so that we don't end up importing
 # all the repository's history.
-bzr checkout --lightweight "$url" -r "$revision" "$out"
+bzr -Ossl.cert_reqs=none export -r "$revision" --format=dir "$out" "$url"
 
 stopNest
diff --git a/pkgs/build-support/fetchbzr/nix-prefetch-bzr b/pkgs/build-support/fetchbzr/nix-prefetch-bzr
index 167892fbb79..9ff86c20ae3 100755
--- a/pkgs/build-support/fetchbzr/nix-prefetch-bzr
+++ b/pkgs/build-support/fetchbzr/nix-prefetch-bzr
@@ -50,12 +50,7 @@ if test -z "$finalPath"; then
     trap "rm -rf $tmpPath" EXIT
 
     # Perform the checkout.
-    if test "$NIX_PREFETCH_BZR_LEAVE_DOT_BZR" != 1
-    then
-        bzr export $revarg "$tmpFile" "$url" >&2
-    else
-        bzr checkout --lightweight $revarg "$url" "$tmpFile" >&2
-    fi
+    bzr -Ossl.cert_reqs=none export $revarg --format=dir "$tmpFile" "$url"
 
     # Compute the hash.
     hash=$(nix-hash --type $hashType $hashFormat $tmpFile)