diff --git a/tool/run/boot_dir/sel4 b/tool/run/boot_dir/sel4
index 966eca3c2..249026042 100644
--- a/tool/run/boot_dir/sel4
+++ b/tool/run/boot_dir/sel4
@@ -14,7 +14,12 @@ proc kernel_files          { } { return sel4 }
 proc run_boot_string   { } { return "\n\rBooting all finished, dropped to user space" }
 proc core_link_address { } { return "0x02000000" }
 
-proc sel4_elfloader_dir { } { return "[pwd]/var/libcache/kernel-sel4/elfloader" }
+proc sel4_elfloader_dir { } {
+	if {![file exists [pwd]/var/libcache/kernel-sel4/elfloader]} {
+		build LIB=kernel-sel4
+	}
+	return "[pwd]/var/libcache/kernel-sel4/elfloader"
+}
 
 ##
 # Populate boot directory with binaries on hw