diff --git a/pkgs/build-support/setup-hooks/separate-debug-info.sh b/pkgs/build-support/setup-hooks/separate-debug-info.sh
index 3a16ac4fee90..197e8a920b70 100644
--- a/pkgs/build-support/setup-hooks/separate-debug-info.sh
+++ b/pkgs/build-support/setup-hooks/separate-debug-info.sh
@@ -1,7 +1,7 @@
 export NIX_SET_BUILD_ID=1
 export NIX_LDFLAGS+=" --compress-debug-sections=zlib"
 export NIX_CFLAGS_COMPILE+=" -ggdb -Wa,--compress-debug-sections"
-export RUSTFLAGS+=" -g"
+export NIX_RUSTFLAGS+=" -g"
 
 fixupOutputHooks+=(_separateDebugInfo)