diff --git a/pkgs/stdenv/generic/setup.sh b/pkgs/stdenv/generic/setup.sh
index 1861b044a394..1f596ada5a0b 100644
--- a/pkgs/stdenv/generic/setup.sh
+++ b/pkgs/stdenv/generic/setup.sh
@@ -29,13 +29,23 @@ if [ -n "$__structuredAttrs" ]; then
         export "$outputName=${outputs[$outputName]}"
     done
 
+    # Before Nix 2.4, $NIX_ATTRS_*_FILE was named differently:
+    # https://github.com/NixOS/nix/commit/27ce722
+    if [[ -n "${ATTRS_JSON_FILE:-}" ]]; then
+        export NIX_ATTRS_JSON_FILE="$ATTRS_JSON_FILE"
+    fi
+
+    if [[ -n "${ATTRS_SH_FILE:-}" ]]; then
+        export NIX_ATTRS_SH_FILE="$ATTRS_SH_FILE"
+    fi
+
     # $NIX_ATTRS_JSON_FILE pointed to the wrong location in sandbox
     # https://github.com/NixOS/nix/issues/6736; please keep around until the
     # fix reaches *every patch version* that's >= lib/minver.nix
-    if ! [[ -e "$NIX_ATTRS_JSON_FILE" ]]; then
+    if ! [[ -e "${NIX_ATTRS_JSON_FILE:-}" ]]; then
         export NIX_ATTRS_JSON_FILE="$NIX_BUILD_TOP/.attrs.json"
     fi
-    if ! [[ -e "$NIX_ATTRS_SH_FILE" ]]; then
+    if ! [[ -e "${NIX_ATTRS_SH_FILE:-}" ]]; then
         export NIX_ATTRS_SH_FILE="$NIX_BUILD_TOP/.attrs.sh"
     fi
 else