diff --git a/repos/base/src/lib/startup/spec/arm/crt0.s b/repos/base/src/lib/startup/spec/arm/crt0.s
index c28d2193ee..17a2394e84 100644
--- a/repos/base/src/lib/startup/spec/arm/crt0.s
+++ b/repos/base/src/lib/startup/spec/arm/crt0.s
@@ -28,6 +28,8 @@
 	/* make initial value of some registers available to higher-level code */
 	ldr r4, =__initial_sp
 	str sp, [r4]
+	ldr r4, =__initial_r0
+	str r0, [r4]
 
 	/*
 	 * Install initial temporary environment that is replaced later by the
@@ -66,3 +68,7 @@
 	.global __initial_sp
 	__initial_sp:
 	.space 4
+	/* initial value of the R0 register */
+	.global __initial_r0
+	__initial_r0:
+	.space 4