diff --git a/exosphere/program/source/secmon_setup.cpp b/exosphere/program/source/secmon_setup.cpp
index 5e33002b8..0136a72d8 100644
--- a/exosphere/program/source/secmon_setup.cpp
+++ b/exosphere/program/source/secmon_setup.cpp
@@ -814,6 +814,16 @@ namespace ams::secmon {
             reg::Read(MC + MC_IRAM_REG_CTRL);
         }
 
+        void DisableUntranslatedDeviceMemoryAccess() {
+            /* If we can (mariko only), disable GMMU accesses that bypass the SMMU. */
+            /* Additionally, force all untranslated acccesses to hit one of the carveouts. */
+            if (GetSocType() == fuse::SocType_Mariko) {
+                reg::Write(MC + MC_UNTRANSLATED_REGION_CHECK, MC_REG_BITS_ENUM(UNTRANSLATED_REGION_CHECK_UNTRANSLATED_REGION_CHECK_ACCESS,          DISABLED),
+                                                              MC_REG_BITS_ENUM(UNTRANSLATED_REGION_CHECK_REQUIRE_UNTRANSLATED_CLIENTS_HIT_CARVEOUT,  ENABLED),
+                                                              MC_REG_BITS_ENUM(UNTRANSLATED_REGION_CHECK_REQUIRE_UNTRANSLATED_GPU_HIT_CARVEOUT,      ENABLED));
+            }
+        }
+
         void FinalizeCarveoutSecureScratchRegisters() {
             /* Define carveout scratch values. */
             constexpr uintptr_t WarmbootCarveoutAddress = MemoryRegionDram.GetAddress();
@@ -1145,6 +1155,9 @@ namespace ams::secmon {
         /* Disable the ARC. */
         DisableArc();
 
+        /* Disable untranslated memory accesses by devices. */
+        DisableUntranslatedDeviceMemoryAccess();
+
         /* Further protections aren't applied on <= 1.0.0. */
         if (GetTargetFirmware() <= TargetFirmware_1_0_0) {
             return;
diff --git a/exosphere/warmboot/source/warmboot_main.cpp b/exosphere/warmboot/source/warmboot_main.cpp
index 8da3af85f..e006ce8b7 100644
--- a/exosphere/warmboot/source/warmboot_main.cpp
+++ b/exosphere/warmboot/source/warmboot_main.cpp
@@ -103,4 +103,6 @@ namespace ams::diag {
         warmboot::ExceptionHandler();
     }
 
+    #include <exosphere/diag/diag_detailed_assertion_impl.inc>
+
 }
diff --git a/libraries/libvapours/include/vapours/tegra/tegra_mc.hpp b/libraries/libvapours/include/vapours/tegra/tegra_mc.hpp
index 093842554..3b44a2769 100644
--- a/libraries/libvapours/include/vapours/tegra/tegra_mc.hpp
+++ b/libraries/libvapours/include/vapours/tegra/tegra_mc.hpp
@@ -163,6 +163,7 @@
 #define MC_EMEM_ARB_TIMING_CCDMW                (0x6C4)
 #define MC_EMEM_ARB_REFPB_HP_CTRL               (0x6F0)
 #define MC_EMEM_ARB_REFPB_BANK_CTRL             (0x6F4)
+#define MC_UNTRANSLATED_REGION_CHECK            (0x948)
 #define MC_PTSA_GRANT_DECREMENT                 (0x960)
 #define MC_CLIENT_HOTRESET_CTRL_1               (0x970)
 #define MC_CLIENT_HOTRESET_STATUS_1             (0x974)
@@ -553,3 +554,6 @@ DEFINE_MC_REG(IRAM_TOM_IRAM_TOM, 12, BITSIZEOF(u32) - 12);
 
 DEFINE_MC_REG_BIT_ENUM(IRAM_REG_CTRL_IRAM_CFG_WRITE_ACCESS, 0, ENABLED, DISABLED);
 
+DEFINE_MC_REG_BIT_ENUM(UNTRANSLATED_REGION_CHECK_UNTRANSLATED_REGION_CHECK_ACCESS,          0, ENABLED, DISABLED);
+DEFINE_MC_REG_BIT_ENUM(UNTRANSLATED_REGION_CHECK_REQUIRE_UNTRANSLATED_CLIENTS_HIT_CARVEOUT, 8, DISABLED, ENABLED);
+DEFINE_MC_REG_BIT_ENUM(UNTRANSLATED_REGION_CHECK_REQUIRE_UNTRANSLATED_GPU_HIT_CARVEOUT,     9, DISABLED, ENABLED);