diff --git a/qemu/target/arm/translate.c b/qemu/target/arm/translate.c
index 15946d46..b4701ddd 100644
--- a/qemu/target/arm/translate.c
+++ b/qemu/target/arm/translate.c
@@ -11090,7 +11090,6 @@ static void disas_thumb2_insn(DisasContext *s, uint32_t insn)
 static void disas_thumb_insn(DisasContext *s, uint32_t insn)
 {
     TCGContext *tcg_ctx = s->uc->tcg_ctx;
-    uint32_t val;
     int32_t offset;
     TCGv_i32 tmp;
     TCGv_i32 tmp2;
@@ -11136,12 +11135,8 @@ static void disas_thumb_insn(DisasContext *s, uint32_t insn)
             gen_bx(s, tmp);
             break;
         }
-        /* unconditional branch */
-        val = read_pc(s);
-        offset = ((int32_t)insn << 21) >> 21;
-        val += offset << 1;
-        gen_jmp(s, val);
-        break;
+        /* unconditional branch, in decodetree */
+        goto illegal_op;
 
     case 15:
         /* thumb_insn_is_16bit() ensures we can't get here for