diff --git a/flake.nix b/flake.nix
index 500d77e..06f0db8 100644
--- a/flake.nix
+++ b/flake.nix
@@ -62,6 +62,9 @@
                         riscv64-linux.binutils
                         riscv64-linux.glibc
                       ];
+                      shellHook = ''
+                        export CROSS_PREFIX="riscv64-none-elf"
+                      '';
                     };
                 }
               ) { };
diff --git a/rv_tests/hello_world/Makefile b/rv_tests/hello_world/Makefile
index 7a70dc4..f362111 100644
--- a/rv_tests/hello_world/Makefile
+++ b/rv_tests/hello_world/Makefile
@@ -1,9 +1,9 @@
 # RISC-V toolchain
-PREFIX = riscv64-unknown-elf
-CC = $(PREFIX)-gcc
-AS = $(PREFIX)-as
-LD = $(PREFIX)-ld
-OBJCOPY = $(PREFIX)-objcopy
+CROSS_PREFIX ?= riscv64-unknown-elf
+CC = $(CROSS_PREFIX)-gcc
+AS = $(CROSS_PREFIX)-as
+LD = $(CROSS_PREFIX)-ld
+OBJCOPY = $(CROSS_PREFIX)-objcopy
 QEMU = qemu-system-riscv64
 
 # Compilation flags