diff --git a/arch/LoongArch/LoongArchMapping.c b/arch/LoongArch/LoongArchMapping.c
index b32e42c685..e8a3746832 100644
--- a/arch/LoongArch/LoongArchMapping.c
+++ b/arch/LoongArch/LoongArchMapping.c
@@ -180,6 +180,9 @@ void LoongArch_rewrite_memory_operand(MCInst *MI)
 
 	const loongarch_suppl_info *suppl_info =
 		map_get_suppl_info(MI, loongarch_insns);
+	if (!suppl_info)
+		return;
+
 	if (suppl_info->memory_access == CS_AC_INVALID) {
 		// not memory instruction
 		return;
diff --git a/arch/Xtensa/XtensaDisassembler.c b/arch/Xtensa/XtensaDisassembler.c
index 3f53a7bde2..0fb216758c 100644
--- a/arch/Xtensa/XtensaDisassembler.c
+++ b/arch/Xtensa/XtensaDisassembler.c
@@ -211,7 +211,7 @@ static DecodeStatus DecodeMR01RegisterClass(MCInst *Inst, uint64_t RegNo,
 					    uint64_t Address,
 					    const void *Decoder)
 {
-	if (RegNo > 2)
+	if (RegNo >= ARR_SIZE(MR01DecoderTable))
 		return MCDisassembler_Fail;
 
 	unsigned Reg = MR01DecoderTable[RegNo];
@@ -970,7 +970,7 @@ static DecodeStatus readInstructionN(const uint8_t *Bytes, size_t BytesLen,
 
 	*Insn = 0;
 	for (unsigned i = 0; i < InstSize; i++)
-		*Insn |= (Bytes[i] << 8 * i);
+		*Insn |= (uint64_t)(Bytes[i]) << (8 * i);
 
 	*Size = InstSize;
 	return MCDisassembler_Success;