diff --git a/Rsconscript b/Rsconscript
index 9b175a5..bc2b456 100644
--- a/Rsconscript
+++ b/Rsconscript
@@ -162,7 +162,10 @@ hello_env = env "hello", use: %w[ldc2 x86_64-w64-mingw32-gcc] do |env|
   env.add_builder(CheckThreadLocal)
   env.add_builder(HulkBinObj)
   env["sources"] = glob("src/hello/**/*.d")
-  env["sources"] += ["src/hulk/writef.d"]
+  env["sources"] += %w[
+    src/hulk/serial.d
+    src/hulk/writef.d
+  ]
   env["sources"] += glob("uefi-d/source/**/*.d")
   env.HulkBinObj("^/hulk_bin.S", hulk_env.expand("^/hulk.bin"))
   env.Object("^/hulk_bin.o", "^/hulk_bin.S")
diff --git a/src/hello/hello.d b/src/hello/hello.d
index 1109b9a..a2d45c5 100644
--- a/src/hello/hello.d
+++ b/src/hello/hello.d
@@ -11,6 +11,7 @@ import hulk.pagetable;
 import hulk.cpu;
 import hulk.memory;
 import ldc.llvmasm;
+import hulk.serial;
 
 __gshared EFI_SYSTEM_TABLE * st;
 /** HULK binary start address, 4KB-aligned. */
@@ -205,6 +206,7 @@ private void get_memory_map(ulong * physical_address_limit, UINTN * memory_map_k
         }
         if (descriptor.Type >= efi_to_hulk_memory_map_type.length)
         {
+            Serial.writefln("Unexpected descriptor type %u", descriptor.Type);
             continue;
         }
         bootinfo().memory_map[count].base = descriptor.PhysicalStart;
@@ -217,6 +219,7 @@ private void get_memory_map(ulong * physical_address_limit, UINTN * memory_map_k
             bootinfo().bss_phys = bootinfo().memory_map[count].base;
             bootinfo().memory_map[count].base += hulk_bss_size();
             bootinfo().memory_map[count].size -= hulk_bss_size();
+            Serial.writefln("Locating HULK BSS at %x", bootinfo().bss_phys);
             found_bss = true;
         }
         if ((!found_stack) &&
@@ -226,6 +229,7 @@ private void get_memory_map(ulong * physical_address_limit, UINTN * memory_map_k
             bootinfo().stack_phys = bootinfo().memory_map[count].base;
             bootinfo().memory_map[count].base += hulk_stack_size();
             bootinfo().memory_map[count].size -= hulk_stack_size();
+            Serial.writefln("Locating HULK stack at %x", bootinfo().stack_phys);
             found_stack = true;
         }
         if ((!found_fb_buffer1) &&
@@ -235,8 +239,13 @@ private void get_memory_map(ulong * physical_address_limit, UINTN * memory_map_k
             bootinfo().fb_buffer1_phys = bootinfo().memory_map[count].base;
             bootinfo().memory_map[count].base += fb_size;
             bootinfo().memory_map[count].size -= fb_size;
+            Serial.writefln("Locating HULK FB1 at %x", bootinfo().fb_buffer1_phys);
             found_fb_buffer1 = true;
         }
+        Serial.writefln("Memory range %x:%x (%u)",
+                bootinfo().memory_map[count].base,
+                bootinfo().memory_map[count].base + bootinfo().memory_map[count].size - 1u,
+                bootinfo().memory_map[count].type);
     }
     bootinfo().memory_map_count = count;
     if ((!found_bss) || (!found_stack) || (!found_fb_buffer1))