diff --git a/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify.nim b/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify.nim
index c6d4a9165..31c080d81 100644
--- a/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify.nim
+++ b/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify.nim
@@ -53,7 +53,7 @@ proc makePairsAndVerify*(vk: VerificationKey,
   let sha256ofHashes = hashHeaders(currentHeaderHash, newOptimisticHeader,
                                    newFinalizedHeader, newExecutionStateRoot,
                                    zerosSlotBuffer, reverseSlot, domain)
-  let header = headerFromSeq(@sha256ofHashes)
+  let header = headerFromArr(sha256ofHashes)
 
   var preparedInputs:Input
   var ic0Prj: ECP_ShortW_Prj[Fp[BN254_Snarks], G1]
diff --git a/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify_helpers.nim b/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify_helpers.nim
index 92594c001..ab349e41c 100644
--- a/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify_helpers.nim
+++ b/contracts/cosmos/verifier/verifier-constantine/lib/nim/verify/verify_helpers.nim
@@ -16,7 +16,7 @@ type
     head*: Fr[BN254_Snarks]
     tail*: Fr[BN254_Snarks]
 
-proc headerFromSeq*(bigNum: seq): Header =
+proc headerFromArr*(bigNum: array[32, byte]): Header =
   var firstNumInBits: array[256, int]
   for i in 0..2:
     firstNumInBits[i] = 0
@@ -62,8 +62,7 @@ proc headerFromSeq*(bigNum: seq): Header =
   var
     head: Fr[BN254_Snarks]
     tail: Fr[BN254_Snarks]
-  head.fromHex(toHex(firstNumInBytes))
-  tail.fromHex(toHex(secondNumInBytes))
-
+  head.fromBig(BigInt[254].unmarshal(firstNumInBytes, bigEndian))
+  tail.fromBig(BigInt[254].unmarshal(secondNumInBytes, bigEndian))
 
   Header(head: head, tail: tail)
diff --git a/libs/nim/verify-utils/verify_given_proof_constantine.nim b/libs/nim/verify-utils/verify_given_proof_constantine.nim
index 53ec7db40..ade6d5600 100644
--- a/libs/nim/verify-utils/verify_given_proof_constantine.nim
+++ b/libs/nim/verify-utils/verify_given_proof_constantine.nim
@@ -106,7 +106,7 @@ proc createHeader*(pathCurrentHeader: string, updatePath: string, domain: string
                                    currentSlot,
                                    domain)
 
-  headerFromSeq(@sha256ofHashes)
+  headerFromArr(sha256ofHashes)
 
 proc makePairsAndVerify*(vk: VerificationKey,
                          prf: Proof,