diff --git a/index/gp/gprbuild/gprbuild-21.0.0-1.toml b/index/gp/gprbuild/gprbuild-21.0.0-1.toml
index e247b342..10b0133b 100644
--- a/index/gp/gprbuild/gprbuild-21.0.0-1.toml
+++ b/index/gp/gprbuild/gprbuild-21.0.0-1.toml
@@ -7,7 +7,7 @@ maintainers-logins = ["Fabien-Chouteau"]
 auto-gpr-with = false
 
 [environment]
-PATH.append = "${CRATE_ROOT}/bin"
+PATH.prepend = "${CRATE_ROOT}/bin"
 
 [origin."case(os)".linux."case(word-size)".bits-64]
 url = "https://github.com/alire-project/GNAT-FSF-builds/releases/download/gprbuild-21.0.0-1/gprbuild-x86_64-linux-21.0.0-1.tar.gz"