diff --git a/evm/src/cpu/kernel/tests/bn254.rs b/evm/src/cpu/kernel/tests/bn254.rs
index e8bf3f28..dba87b96 100644
--- a/evm/src/cpu/kernel/tests/bn254.rs
+++ b/evm/src/cpu/kernel/tests/bn254.rs
@@ -12,9 +12,9 @@ use crate::extension_tower::{FieldExt, Fp12, Fp2, Fp6, Stack, BN254};
 use crate::memory::segments::Segment::BnPairing;
 
 fn run_bn_mul_fp6(f: Fp6<BN254>, g: Fp6<BN254>, label: &str) -> Fp6<BN254> {
-    let mut stack = f.to_stack();
+    let mut stack = f.to_stack().to_vec();
     if label == "mul_fp254_6" {
-        stack.extend(g.to_stack());
+        stack.extend(g.to_stack().to_vec());
     }
     stack.push(U256::from(0xdeadbeefu32));
     let setup = InterpreterMemoryInitialization {
@@ -61,7 +61,7 @@ fn run_bn_mul_fp12(f: Fp12<BN254>, g: Fp12<BN254>, label: &str) -> Fp12<BN254> {
         label: label.to_string(),
         stack,
         segment: BnPairing,
-        memory: vec![(in0, f.to_stack()), (in1, g.to_stack())],
+        memory: vec![(in0, f.to_stack().to_vec()), (in1, g.to_stack().to_vec())],
     };
     let interpreter = run_interpreter_with_memory(setup).unwrap();
     let output = interpreter.extract_kernel_memory(BnPairing, out..out + 12);
@@ -89,7 +89,7 @@ fn test_bn_mul_fp12() -> Result<()> {
 fn run_bn_frob_fp6(n: usize, f: Fp6<BN254>) -> Fp6<BN254> {
     let setup = InterpreterMemoryInitialization {
         label: format!("test_frob_fp254_6_{}", n),
-        stack: f.to_stack(),
+        stack: f.to_stack().to_vec(),
         segment: BnPairing,
         memory: vec![],
     };
@@ -115,7 +115,7 @@ fn run_bn_frob_fp12(n: usize, f: Fp12<BN254>) -> Fp12<BN254> {
         label: format!("test_frob_fp254_12_{}", n),
         stack: vec![U256::from(ptr)],
         segment: BnPairing,
-        memory: vec![(ptr, f.to_stack())],
+        memory: vec![(ptr, f.to_stack().to_vec())],
     };
     let interpeter: Interpreter = run_interpreter_with_memory(setup).unwrap();
     let output: Vec<U256> = interpeter.extract_kernel_memory(BnPairing, ptr..ptr + 12);
@@ -144,7 +144,7 @@ fn test_bn_inv_fp12() -> Result<()> {
         label: "inv_fp254_12".to_string(),
         stack: vec![U256::from(ptr), U256::from(inv), U256::from(0xdeadbeefu32)],
         segment: BnPairing,
-        memory: vec![(ptr, f.to_stack())],
+        memory: vec![(ptr, f.to_stack().to_vec())],
     };
     let interpreter: Interpreter = run_interpreter_with_memory(setup).unwrap();
     let output: Vec<U256> = interpreter.extract_kernel_memory(BnPairing, inv..inv + 12);
@@ -165,12 +165,12 @@ fn test_bn_final_exponentiation() -> Result<()> {
         label: "bn254_invariant_exponent".to_string(),
         stack: vec![U256::from(ptr), U256::from(0xdeadbeefu32)],
         segment: BnPairing,
-        memory: vec![(ptr, f.to_stack())],
+        memory: vec![(ptr, f.to_stack().to_vec())],
     };
 
     let interpreter: Interpreter = run_interpreter_with_memory(setup).unwrap();
     let output: Vec<U256> = interpreter.extract_kernel_memory(BnPairing, ptr..ptr + 12);
-    let expected: Vec<U256> = invariant_exponent(f).to_stack();
+    let expected: Vec<U256> = invariant_exponent(f).to_stack().to_vec();
 
     assert_eq!(output, expected);
 
@@ -250,7 +250,7 @@ fn test_bn_miller_loop() -> Result<()> {
     };
     let interpreter = run_interpreter_with_memory(setup).unwrap();
     let output: Vec<U256> = interpreter.extract_kernel_memory(BnPairing, out..out + 12);
-    let expected = miller_loop(CURVE_GENERATOR, TWISTED_GENERATOR).to_stack();
+    let expected = miller_loop(CURVE_GENERATOR, TWISTED_GENERATOR).to_stack().to_vec();
 
     assert_eq!(output, expected);
 
@@ -278,7 +278,7 @@ fn test_bn_tate_pairing() -> Result<()> {
     };
     let interpreter = run_interpreter_with_memory(setup).unwrap();
     let output: Vec<U256> = interpreter.extract_kernel_memory(BnPairing, out..out + 12);
-    let expected = tate(CURVE_GENERATOR, TWISTED_GENERATOR).to_stack();
+    let expected = tate(CURVE_GENERATOR, TWISTED_GENERATOR).to_stack().to_vec();
 
     assert_eq!(output, expected);
 
diff --git a/evm/src/extension_tower.rs b/evm/src/extension_tower.rs
index d166152e..851fcd61 100644
--- a/evm/src/extension_tower.rs
+++ b/evm/src/extension_tower.rs
@@ -1,8 +1,6 @@
-use std::mem::transmute;
 use std::ops::{Add, Div, Mul, Neg, Sub};
 
 use ethereum_types::{U256, U512};
-use plonky2::field::types::Field;
 use rand::distributions::{Distribution, Standard};
 use rand::Rng;
 
@@ -1251,61 +1249,63 @@ impl<T: FieldExt + Stack> Stack for Fp2<T> {
     }
 
     fn from_stack(stack: &[U256]) -> Fp2<T> {
-        let re = T::from_stack(&stack[0..2]);
-        let im = T::from_stack(&stack[2..4]);
+        let field_size = T::SIZE;
+        let re = T::from_stack(&stack[0..field_size]);
+        let im = T::from_stack(&stack[field_size..2*field_size]);
         Fp2 { re, im }
     }
 }
 
-// impl<T> Stack for Fp6<T>
-// where
-//     T: FieldExt,
-//     Fp2<T>: Adj,
-//     Fp2<T>: Stack,
-// {
-//     const SIZE: usize = 3 * Fp2::<T>::SIZE;
+impl<T> Stack for Fp6<T>
+where
+    T: FieldExt,
+    Fp2<T>: Adj,
+    Fp2<T>: Stack,
+{
+    const SIZE: usize = 3 * Fp2::<T>::SIZE;
 
-//     fn to_stack(&self) -> &[U256] {
-//         let t0 = self.t0.to_stack();
-//         let t1 = self.t1.to_stack();
-//         let t2 = self.t2.to_stack();
+    fn to_stack(&self) -> &[U256] {
+        let t0 = self.t0.to_stack();
+        let t1 = self.t1.to_stack();
+        let t2 = self.t2.to_stack();
 
-//         let mut combined: Vec<U256> = Vec::new();
-//         combined.extend_from_slice(t0);
-//         combined.extend_from_slice(t1);
-//         combined.extend_from_slice(t2);
-//         Box::leak(combined.into_boxed_slice())
-//     }
+        let mut combined: Vec<U256> = Vec::new();
+        combined.extend_from_slice(t0);
+        combined.extend_from_slice(t1);
+        combined.extend_from_slice(t2);
+        Box::leak(combined.into_boxed_slice())
+    }
 
-//     fn from_stack(stack: &[U256]) -> Self {
-//         let f = [
-//             T::from_stack(&stack[0..2]),
-//             T::from_stack(&stack[2..4]),
-//             T::from_stack(&stack[4..6]),
-//         ];
-//         f.copy_from_slice(stack);
-//         unsafe { transmute(f) }
-//     }
-// }
+    fn from_stack(stack: &[U256]) -> Self {
+        let field_size = Fp2::<T>::SIZE;
+        let t0 = Fp2::<T>::from_stack(&stack[0..field_size]);
+        let t1 = Fp2::<T>::from_stack(&stack[field_size..2*field_size]);
+        let t2 = Fp2::<T>::from_stack(&stack[2*field_size..3*field_size]);
+        Fp6 { t0, t1, t2 }
+    }
+}
 
-// impl<T> Stack for Fp12<T>
-// where
-//     T: FieldExt,
-//     Fp2<T>: Adj,
-//     Fp6<T>: Stack,{
-//     const SIZE: usize = 2 * Fp6::<T>::SIZE;
+impl<T> Stack for Fp12<T>
+where
+    T: FieldExt,
+    Fp2<T>: Adj,
+    Fp6<T>: Stack,{
+    const SIZE: usize = 2 * Fp6::<T>::SIZE;
 
-//     fn to_stack(&self) -> &[U256] {
-//         let z0 = self.z0.to_stack();
-//         let z1 = self.z1.to_stack();
+    fn to_stack(&self) -> &[U256] {
+        let z0 = self.z0.to_stack();
+        let z1 = self.z1.to_stack();
 
-//         let mut combined: Vec<U256> = Vec::new();
-//         combined.extend_from_slice(z0);
-//         combined.extend_from_slice(z1);
-//         Box::leak(combined.into_boxed_slice())
-//     }
+        let mut combined: Vec<U256> = Vec::new();
+        combined.extend_from_slice(z0);
+        combined.extend_from_slice(z1);
+        Box::leak(combined.into_boxed_slice())
+    }
 
-//     fn from_stack(stack: &[U256]) -> Self {
-//         let f = [T::from_stack(&stack[0..6]), T::from_stack(&stack[6..12])];
-//     }
-// }
+    fn from_stack(stack: &[U256]) -> Self {
+        let field_size = Fp6::<T>::SIZE;
+        let z0 = Fp6::<T>::from_stack(&stack[0..field_size]);
+        let z1 = Fp6::<T>::from_stack(&stack[field_size..2*field_size]);
+        Fp12 { z0, z1 }
+    }
+}