diff --git a/main/ecrecover/constEc.zkasm b/main/ecrecover/constEc.zkasm
index f17f43a2..b858190e 100644
--- a/main/ecrecover/constEc.zkasm
+++ b/main/ecrecover/constEc.zkasm
@@ -1,6 +1,6 @@
 CONSTL %FPEC = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFC2Fn
 CONSTL %FPEC_MINUS_ONE = %FPEC - 1
-CONSTL %FNEC_DIV_TWO = 57896044618658097711785492504343953926418782139537452191302581570759080747169n
+CONSTL %FNEC_DIV_TWO = 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF5D576E7357A4501DDFE92F46681B20A0n
 CONSTL %FPEC_C2_256 = 0x1000003D1n
 CONSTL %FPEC_NON_SQRT = (1n << 256n) - 1n
 
diff --git a/test/ecrecover.zkasm b/test/ecrecover.zkasm
index eb9f904a..354cdf51 100644
--- a/test/ecrecover.zkasm
+++ b/test/ecrecover.zkasm
@@ -329,15 +329,26 @@ repeat_ecrecover_test:
         :CALL(ecrecover_tx)
         0x0000000000000000000000000000000000000000n :ASSERT
 
-        ; #34 s == field/2 + 1. Valid
+        ; #34 s == field/2 + 1. Valid (precompiled)
 
         0x456e9aea5e197a1f1af7a3e85a3212fa4049a3ba34c2289b4c860fc0b0c64ef3n => A
         0x9242685bf161793cc25603c231bc2f568eb630ea16aa137d2664ac8038825608n => B
         0x7fffffffffffffffffffffffffffffff5d576e7357a4501ddfe92f46681b20a1n => C
         0x1cn => D
-        :CALL(ecrecover_tx)
+        :CALL(ecrecover_precompiled)
         0x4ef445CADd8bEe8A02bc79b30A97e6Fe3AE3B7a3n :ASSERT
 
+        ; #34' s == field/2 + 1. Invalid (tx)
+
+        0x456e9aea5e197a1f1af7a3e85a3212fa4049a3ba34c2289b4c860fc0b0c64ef3n => A
+        0x9242685bf161793cc25603c231bc2f568eb630ea16aa137d2664ac8038825608n => B
+        0x7fffffffffffffffffffffffffffffff5d576e7357a4501ddfe92f46681b20a1n => C
+        0x1cn => D
+        :CALL(ecrecover_tx)
+        0n :ASSERT
+        B => A
+        4n :ASSERT
+
         ; #35 s == field/2. Valid
 
         0x456e9aea5e197a1f1af7a3e85a3212fa4049a3ba34c2289b4c860fc0b0c64ef3n => A