diff --git a/app/src/parser/operation_parser.c b/app/src/parser/operation_parser.c
index 91c7d72f8..185812cca 100644
--- a/app/src/parser/operation_parser.c
+++ b/app/src/parser/operation_parser.c
@@ -415,7 +415,7 @@ tz_step_size(tz_parser_state *state)
         tz_raise(TOO_LARGE);  // enforce 16-bit restriction
     op->frame->step_size.size = op->frame->step_size.size << 8 | b;
     op->frame->step_size.size_len--;
-    if (op->frame->step_size.size_len <= 0) {
+    if (op->frame->step_size.size_len == 0) {
         op->frame[-1].stop = state->ofs + op->frame->step_size.size;
         tz_must(pop_frame(state));
     }
@@ -576,7 +576,7 @@ tz_step_read_int32(tz_parser_state *state)
     ASSERT_STEP(state, READ_INT32);
     tz_operation_state *op = &state->operation;
     uint8_t             b;
-    uint32_t           *value = &op->frame->step_read_int32.value;
+    int32_t           *value = &op->frame->step_read_int32.value;
     if (op->frame->step_read_int32.ofs < 4) {
         tz_must(tz_parser_read(state, &b));
         *value = *value << 8 | b;
diff --git a/app/src/parser/operation_state.h b/app/src/parser/operation_state.h
index a9ec5efa8..a8678675e 100644
--- a/app/src/parser/operation_state.h
+++ b/app/src/parser/operation_state.h
@@ -147,7 +147,7 @@ typedef struct {
             uint8_t                 skip : 1, natural : 1;
         } step_read_num;
         struct {
-            uint32_t value;
+            int32_t value;
             uint8_t  skip : 1, ofs : 3;
         } step_read_int32;
         struct {