diff --git a/photon/libc/sys/horizon/heap.c b/photon/libc/sys/horizon/heap.c
index 33a3fd4..c7b0090 100644
--- a/photon/libc/sys/horizon/heap.c
+++ b/photon/libc/sys/horizon/heap.c
@@ -30,6 +30,7 @@ void __crt_heap_init(size_t sz)
             MX_VM_CAN_MAP_READ | MX_VM_CAN_MAP_WRITE | MX_VM_CAN_MAP_SPECIFIC,
             0, HEAP_REGION_SZ, &heap_vmar, &heap);
     if (status != MX_OK) {
+        fprintf(stderr, "fatal: cannot allocate heap virtual region (%s)\n", mx_status_to_string(status));
         abort();
     }
 
@@ -38,6 +39,7 @@ void __crt_heap_init(size_t sz)
             MX_VM_CAN_MAP_READ | MX_VM_CAN_MAP_WRITE | MX_VM_CAN_MAP_SPECIFIC,
             &heap_vmo);
     if (status != MX_OK) {
+        fprintf(stderr, "fatal: cannot allocate heap (%s)\n", mx_status_to_string(status));
         abort();
     }
 
@@ -46,6 +48,7 @@ void __crt_heap_init(size_t sz)
             0, heap_vmo, 0, sz,
             &heap);
     if (status != MX_OK) {
+        fprintf(stderr, "fatal: cannot map heap (%s)\n", mx_status_to_string(status));
         abort();
     }
 
@@ -84,7 +87,7 @@ void *__crt_heap_extend(size_t sz)
             offset, heap_vmo, heap_sz, sz, &alloc_base);
 
     if (err != MX_OK) {
-        printf("cannot map extended heap: %s\n", mx_status_to_string(err));
+        fprintf(stderr, "fatal: cannot map extended heap (%s)\n", mx_status_to_string(err));
         abort();
     }