diff --git a/.circleci/config.yml b/.circleci/config.yml
index b92a302e..ee59e825 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -14,7 +14,7 @@ jobs:
           command: cargo generate-lockfile
       - restore_cache:
           keys:
-            - v5-cargo-cache-{{ arch }}-{{ checksum "Cargo.lock" }}
+            - v4-cargo-cache-{{ arch }}-{{ checksum "Cargo.lock" }}
       - run:
           name: Build libsnark
           command: LIBSNARK_SOURCE_PATH=$HOME/libsnark ./build_libsnark.sh
diff --git a/stdlib/hashes/sha256/512bitPacked.code b/stdlib/hashes/sha256/512bitPacked.code
index 77be38eb..21da2f77 100644
--- a/stdlib/hashes/sha256/512bitPacked.code
+++ b/stdlib/hashes/sha256/512bitPacked.code
@@ -1,7 +1,6 @@
 import "PACKING/pack128" as pack128
 import "PACKING/unpack128" as unpack128
 import "./512bit.code" as sha256
-//FIXME: delete packed stldib
 // A function that takes an array of 4 field elements as inputs, unpacks each of them to 128
 // bits (big endian), concatenates them and applies sha256.
 // It then returns an array of  two field elements, each representing 128 bits of the result.
diff --git a/zokrates_cli/examples/TestStdlib/hashes/sha256/test512bitPadded.code b/zokrates_cli/examples/TestStdlib/hashes/sha256/test512bitPadded.code
index 3c6f2939..06ba66e2 100644
--- a/zokrates_cli/examples/TestStdlib/hashes/sha256/test512bitPadded.code
+++ b/zokrates_cli/examples/TestStdlib/hashes/sha256/test512bitPadded.code
@@ -1,3 +1,17 @@
+// Python code used to create test vector:
+// import hashlib  
+
+// preimage = bytes.fromhex('00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00\
+// 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 05')
+
+// bin(int(preimage.hex(), 16)) 
+// # '0b101'
+
+// digest = hashlib.sha256(preimage).hexdigest() 
+// # digest = 'c6481e22c5ff4164af680b8cfaa5e8ed3120eeff89c4f307c4a6faaae059ce10'
+
+// bin(int(digest, 16))
+// # '0b1100011001001000000111100010001011000101111111110100000101100100101011110110100000001011100011001111101010100101111010001110110100110001001000001110111011111111100010011100010011110011000001111100010010100110111110101010101011100000010110011100111000010000'
 import "hashes/sha256/512bitPadded.code" as sha256
 def main() -> (field):