diff --git a/src/pkg/runtime/mem_netbsd.c b/src/pkg/runtime/mem_netbsd.c
index 63a57b94a3..e5bdac0ef6 100644
--- a/src/pkg/runtime/mem_netbsd.c
+++ b/src/pkg/runtime/mem_netbsd.c
@@ -50,7 +50,7 @@ runtime·SysReserve(void *v, uintptr n)
 		return v;
 
 	p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
-	if(p == (void*)ENOMEM)
+	if(p < (void*)4096)
 		return nil;
 	return p;
 }
diff --git a/src/pkg/runtime/mem_openbsd.c b/src/pkg/runtime/mem_openbsd.c
index 63a57b94a3..e5bdac0ef6 100644
--- a/src/pkg/runtime/mem_openbsd.c
+++ b/src/pkg/runtime/mem_openbsd.c
@@ -50,7 +50,7 @@ runtime·SysReserve(void *v, uintptr n)
 		return v;
 
 	p = runtime·mmap(v, n, PROT_NONE, MAP_ANON|MAP_PRIVATE, -1, 0);
-	if(p == (void*)ENOMEM)
+	if(p < (void*)4096)
 		return nil;
 	return p;
 }