diff --git a/riscv/insns/mfcr.h b/riscv/insns/mfcr.h
index de3c19dc..1c7ec2d7 100644
--- a/riscv/insns/mfcr.h
+++ b/riscv/insns/mfcr.h
@@ -10,9 +10,6 @@ switch(insn.rtype.rs2)
     val = 32; // synci_step
     break;
 
-  case 29:
-    throw trap_illegal_instruction;
-
   default:
     val = -1;
 }