diff --git a/src/arithmetic/fields.rs b/src/arithmetic/fields.rs
index c46ac81..c8f7916 100644
--- a/src/arithmetic/fields.rs
+++ b/src/arithmetic/fields.rs
@@ -160,10 +160,10 @@ impl<F: FieldExt> SqrtHasher<F> {
 pub struct SqrtTables<F: FieldExt> {
     hasher: SqrtHasher<F>,
     inv: Vec<u8>,
-    g0: [F; 256],
-    g1: [F; 256],
-    g2: [F; 256],
-    g3: [F; 129],
+    g0: Box<[F; 256]>,
+    g1: Box<[F; 256]>,
+    g2: Box<[F; 256]>,
+    g3: Box<[F; 129]>,
 }
 
 impl<F: FieldExt> SqrtTables<F> {
@@ -202,10 +202,10 @@ impl<F: FieldExt> SqrtTables<F> {
         SqrtTables::<F> {
             hasher,
             inv,
-            g0: gtab[0][..].try_into().unwrap(),
-            g1: gtab[1][..].try_into().unwrap(),
-            g2: gtab[2][..].try_into().unwrap(),
-            g3: gtab[3][0..129].try_into().unwrap(),
+            g0: Box::new(gtab[0][..].try_into().unwrap()),
+            g1: Box::new(gtab[1][..].try_into().unwrap()),
+            g2: Box::new(gtab[2][..].try_into().unwrap()),
+            g3: Box::new(gtab[3][0..129].try_into().unwrap()),
         }
     }
 
diff --git a/src/pasta/fields/fp.rs b/src/pasta/fields/fp.rs
index f03eb3f..15fa46c 100644
--- a/src/pasta/fields/fp.rs
+++ b/src/pasta/fields/fp.rs
@@ -796,7 +796,6 @@ impl FieldExt for Fp {
         let rr = sqr(rq, 7) * r111;
         let rs = sqr(rr, 3) * r11;
         let rt = rs.square();
-        //assert!(rt == ff::Field::pow_vartime(&self, &Fp::T_MINUS1_OVER2));
         rt
     }
 }
@@ -837,6 +836,13 @@ fn test_sqrt() {
     assert!(v == Fp::TWO_INV || (-v) == Fp::TWO_INV);
 }
 
+#[test]
+fn test_pow_by_t_minus1_over2() {
+    // NB: TWO_INV is standing in as a "random" field element
+    let v = (Fp::TWO_INV).pow_by_t_minus1_over2();
+    assert!(v == ff::Field::pow_vartime(&Fp::TWO_INV, &Fp::T_MINUS1_OVER2));
+}
+
 #[test]
 fn test_sqrt_ratio_and_alt() {
     // (true, sqrt(num/div)), if num and div are nonzero and num/div is a square in the field
diff --git a/src/pasta/fields/fq.rs b/src/pasta/fields/fq.rs
index 64dd760..1241561 100644
--- a/src/pasta/fields/fq.rs
+++ b/src/pasta/fields/fq.rs
@@ -796,7 +796,6 @@ impl FieldExt for Fq {
         let sr = sqr(sq, 5) * s1011;
         let ss = sqr(sr, 3) * self;
         let st = sqr(ss, 4);
-        //assert!(st == ff::Field::pow_vartime(&self, &Fq::T_MINUS1_OVER2));
         st
     }
 }
@@ -837,6 +836,13 @@ fn test_sqrt() {
     assert!(v == Fq::TWO_INV || (-v) == Fq::TWO_INV);
 }
 
+#[test]
+fn test_pow_by_t_minus1_over2() {
+    // NB: TWO_INV is standing in as a "random" field element
+    let v = (Fq::TWO_INV).pow_by_t_minus1_over2();
+    assert!(v == ff::Field::pow_vartime(&Fq::TWO_INV, &Fq::T_MINUS1_OVER2));
+}
+
 #[test]
 fn test_sqrt_ratio_and_alt() {
     // (true, sqrt(num/div)), if num and div are nonzero and num/div is a square in the field
diff --git a/src/poly/commitment.rs b/src/poly/commitment.rs
index a9b6c74..11e9d9e 100644
--- a/src/poly/commitment.rs
+++ b/src/poly/commitment.rs
@@ -38,8 +38,8 @@ impl<C: CurveAffine> Params<C> {
         // This is usually a limitation on the curve, but we also want 32-bit
         // architectures to be supported.
         assert!(k < 32);
-        // No goofy hardware please.
-        assert!(core::mem::size_of::<usize>() >= 4);
+
+        // In src/arithmetic/fields.rs we ensure that usize is at least 32 bits.
 
         let n: u64 = 1 << k;