diff --git a/modules/arch/x86/gen_x86_insn.py b/modules/arch/x86/gen_x86_insn.py
index 99d26ff2..ba41a4f1 100755
--- a/modules/arch/x86/gen_x86_insn.py
+++ b/modules/arch/x86/gen_x86_insn.py
@@ -691,6 +691,14 @@ add_group("threebyte",
     opcode=[0x00, 0x00, 0x00],
     operands=[])
 
+#
+# Four byte opcode instructions with no operands
+#
+add_group("fourbyte",
+    modifiers=["Op0Add", "Op1Add", "Op2Add", "Op3Add"],
+    opcode=[0x00, 0x00, 0x00, 0x00],
+    operands=[])
+
 #
 # One byte opcode instructions with general memory operand
 #
@@ -5475,6 +5483,9 @@ add_group("vmxthreebytemem",
 add_insn("vmclear", "vmxthreebytemem", modifiers=[0x66])
 add_insn("vmxon", "vmxthreebytemem", modifiers=[0xF3])
 
+add_insn("endbr32", "fourbyte", modifiers=[0xF3, 0x0F, 0x1E, 0xFB])
+add_insn("endbr64", "fourbyte", modifiers=[0xF3, 0x0F, 0x1E, 0xFA])
+
 #####################################################################
 # Intel SMX Instructions
 #####################################################################