diff --git a/arch/ARM/ARMMapping.c b/arch/ARM/ARMMapping.c
index bbb10fda..fc78578e 100644
--- a/arch/ARM/ARMMapping.c
+++ b/arch/ARM/ARMMapping.c
@@ -2332,19 +2332,6 @@ void ARM_get_insn_id(cs_struct *h, cs_insn *insn, unsigned int id)
 	}
 }
 
-unsigned int ARM_get_insn_id2(unsigned int id)
-{
-	unsigned int i;
-
-	for (i = 0; i < ARR_SIZE(insns); i++) {
-		if (id == insns[i].mapid)
-			return insns[i].id;
-	}
-
-	// found nothing
-	return 0;
-}
-
 static name_map insn_name_maps[] = {
 	{ ARM_INS_INVALID, NULL },
 
diff --git a/arch/ARM/ARMMapping.h b/arch/ARM/ARMMapping.h
index e6149f12..1f2ed727 100644
--- a/arch/ARM/ARMMapping.h
+++ b/arch/ARM/ARMMapping.h
@@ -14,9 +14,6 @@ const char *ARM_reg_name(csh handle, unsigned int reg);
 // given internal insn id, return public instruction ID
 void ARM_get_insn_id(cs_struct *h, cs_insn *insn, unsigned int id);
 
-// given public insn id, return internal instruction info
-unsigned int ARM_get_insn_id2(unsigned int id);
-
 const char *ARM_insn_name(csh handle, unsigned int id);
 
 // map instruction name to instruction ID
diff --git a/arch/PowerPC/PPCMapping.c b/arch/PowerPC/PPCMapping.c
index 6d0f41af..87699555 100644
--- a/arch/PowerPC/PPCMapping.c
+++ b/arch/PowerPC/PPCMapping.c
@@ -981,18 +981,6 @@ void PPC_get_insn_id(cs_struct *h, cs_insn *insn, unsigned int id)
 	}
 }
 
-// given public insn id, return internal insn id
-unsigned int PPC_get_insn_id2(unsigned int id)
-{
-	// consider alias insn first
-	unsigned int res;
-	res = insn_reverse_id(alias_insns, ARR_SIZE(alias_insns), id);
-	if (res)
-		return res;
-
-	return insn_reverse_id(insns, ARR_SIZE(insns), id);
-}
-
 static name_map insn_name_maps[] = {
 	{ PPC_INS_INVALID, NULL },
 
diff --git a/arch/PowerPC/PPCMapping.h b/arch/PowerPC/PPCMapping.h
index a1919116..b6975a06 100644
--- a/arch/PowerPC/PPCMapping.h
+++ b/arch/PowerPC/PPCMapping.h
@@ -13,10 +13,6 @@ const char *PPC_reg_name(csh handle, unsigned int reg);
 // given internal insn id, return public instruction info
 void PPC_get_insn_id(cs_struct *h, cs_insn *insn, unsigned int id);
 
-// given public insn id, return internal insn id
-unsigned int PPC_get_insn_id2(unsigned int id);
-
-// given public insn id, return internal insn id
 const char *PPC_insn_name(csh handle, unsigned int id);
 
 // map instruction name to instruction ID