diff --git a/packages/genodelabs/core-diag.patch b/packages/genodelabs/core-diag.patch
new file mode 100644
index 0000000..92444bd
--- /dev/null
+++ b/packages/genodelabs/core-diag.patch
@@ -0,0 +1,39 @@
+From e5da4aa414e19b808e544e7bd89888cc7a3b85d3 Mon Sep 17 00:00:00 2001
+From: Emery Hemingway <ehmry@posteo.net>
+Date: Sat, 7 Nov 2020 08:37:29 +0100
+Subject: [PATCH] core: log ROM requests with affirmative "diag" flag
+
+---
+ repos/base/src/core/include/rom_session_component.h | 12 ++++++++++--
+ 1 file changed, 10 insertions(+), 2 deletions(-)
+
+diff --git a/repos/base/src/core/include/rom_session_component.h b/repos/base/src/core/include/rom_session_component.h
+index c584701f5f..2c9623afcf 100644
+--- a/repos/base/src/core/include/rom_session_component.h
++++ b/repos/base/src/core/include/rom_session_component.h
+@@ -35,12 +35,20 @@ namespace Genode {
+ 			{
+ 				/* extract label */
+ 				Session_label const label = label_from_args(args);
++				auto const name = label.last_element();
++
++				/* extract diag flag */
++				bool diag = session_diag_from_args(args).enabled;
+ 
+ 				/* find ROM module for trailing label element */
+-				Rom_module const * rom = rom_fs.find(label.last_element().string());
+-				if (rom)
++				Rom_module const * rom = rom_fs.find(name.string());
++
++				if (rom) {
++					if (diag) log("serve ROM \"", name, "\" to \"", label, "\"");
+ 					return *rom;
++				}
+ 
++				if (diag) error("ROM \"", name, "\" not found for \"", label, "\"");
+ 				throw Service_denied();
+ 			}
+ 
+-- 
+2.28.0
+
diff --git a/packages/genodelabs/default.nix b/packages/genodelabs/default.nix
index 06f33eb..ab43ae7 100644
--- a/packages/genodelabs/default.nix
+++ b/packages/genodelabs/default.nix
@@ -296,7 +296,7 @@ let
         '';
     };
 
-  basePatches = [ ./cxx-align.patch ];
+  basePatches = [ ./cxx-align.patch ./core-diag.patch ];
 
 in makePackages // depotPackages // {