diff --git a/cmd/efi_common.c b/cmd/efi_common.c
index 904747c5b32..e57835d3bae 100644
--- a/cmd/efi_common.c
+++ b/cmd/efi_common.c
@@ -58,6 +58,7 @@ static const struct efi_mem_attrs {
 	{EFI_MEMORY_SP, "SP"},
 	{EFI_MEMORY_CPU_CRYPTO, "CRYPT"},
 	{EFI_MEMORY_HOT_PLUGGABLE, "HOTPL"},
+	{EFI_MEMORY_ISA_VALID, "ISA_VALID"},
 	{EFI_MEMORY_RUNTIME, "RT"},
 };
 
@@ -91,13 +92,16 @@ static const char *efi_mem_type_name(u32 type)
  * efi_print_mem_attrs() - print the names of set EFI memory attributes
  *
  * Prints the set attribute bits as a '|'-separated list of mnemonics,
- * e.g. ' UC|WB|RT', preceded by a space. Prints nothing if no known
- * attribute bit is set.
+ * e.g. ' UC|WB|RT', preceded by a space. When EFI_MEMORY_ISA_VALID is
+ * set, the EFI_MEMORY_ISA_MASK field is printed as ISA=<value>. Bits
+ * that have no mnemonic are printed as a hexadecimal value so that
+ * invalid or not yet known attributes are never dropped silently.
  *
  * @attributes: memory attributes (EFI_MEMORY_...)
  */
 static void efi_print_mem_attrs(u64 attributes)
 {
+	u64 unknown = attributes;
 	int sep, i;
 
 	for (sep = 0, i = 0; i < ARRAY_SIZE(efi_mem_attrs); i++)
@@ -109,7 +113,19 @@ static void efi_print_mem_attrs(u64 attributes)
 				sep = 1;
 			}
 			puts(efi_mem_attrs[i].text);
+			unknown &= ~efi_mem_attrs[i].bit;
 		}
+
+	if (attributes & EFI_MEMORY_ISA_VALID) {
+		printf("%sISA=0x%llx", sep ? "|" : " ",
+		       (attributes & EFI_MEMORY_ISA_MASK) >>
+		       EFI_MEMORY_ISA_SHIFT);
+		sep = 1;
+		unknown &= ~EFI_MEMORY_ISA_MASK;
+	}
+
+	if (unknown)
+		printf("%s0x%llx", sep ? "|" : " ", unknown);
 }
 
 void efi_show_memmap(struct efi_mem_desc *map, efi_uintn_t map_size,
diff --git a/doc/usage/cmd/efi.rst b/doc/usage/cmd/efi.rst
index 3ccdbe9410c..62a2638feca 100644
--- a/doc/usage/cmd/efi.rst
+++ b/doc/usage/cmd/efi.rst
@@ -45,7 +45,10 @@ Start, End
 
 Attributes
     The attributes of the region as a '|'-separated list of mnemonics,
-    e.g. UC for EFI_MEMORY_UC and RT for EFI_MEMORY_RUNTIME.
+    e.g. UC for EFI_MEMORY_UC and RT for EFI_MEMORY_RUNTIME. When the
+    region carries ISA-specific attributes (EFI_MEMORY_ISA_VALID is set),
+    the ISA-specific field is shown as ISA=<value>. Attribute bits without
+    a mnemonic are shown as a hexadecimal value.
 
 efi tables
 ~~~~~~~~~~
diff --git a/include/efi.h b/include/efi.h
index 71234d1b6fe..a4c21d7681d 100644
--- a/include/efi.h
+++ b/include/efi.h
@@ -268,6 +268,9 @@ enum efi_memory_type {
 #define EFI_MEMORY_CPU_CRYPTO	((u64)0x0000000000080000ULL)	/* cryptographically protectable */
 #define EFI_MEMORY_HOT_PLUGGABLE \
 				((u64)0x0000000000100000ULL)	/* hot pluggable */
+#define EFI_MEMORY_ISA_MASK	((u64)0x0FFFF00000000000ULL)	/* ISA-specific attributes */
+#define EFI_MEMORY_ISA_SHIFT	44
+#define EFI_MEMORY_ISA_VALID	((u64)0x4000000000000000ULL)	/* ISA_MASK field is valid */
 #define EFI_MEMORY_RUNTIME	((u64)0x8000000000000000ULL)	/* range requires runtime mapping */
 #define EFI_MEM_DESC_VERSION	1
 
@@ -686,7 +689,9 @@ void efi_show_tables(struct efi_system_table *systab);
  *
  * Prints one line per descriptor with the memory type name, the physical
  * start and end address and the attributes as a '|'-separated list of
- * mnemonics.
+ * mnemonics. The ISA-specific attribute field is printed as ISA=<value>
+ * when EFI_MEMORY_ISA_VALID is set, and any remaining bits without a
+ * mnemonic are printed as a hexadecimal value.
  *
  * The virtual addresses of the descriptors are not shown: the map is
  * identity mapped before SetVirtualAddressMap() is called, so the field