diff --git a/eth2/utils/ssz/src/decode/impls.rs b/eth2/utils/ssz/src/decode/impls.rs
index 0965ee3e54..75dd5d444c 100644
--- a/eth2/utils/ssz/src/decode/impls.rs
+++ b/eth2/utils/ssz/src/decode/impls.rs
@@ -34,6 +34,11 @@ impl_decodable_for_uint!(u8, 8);
 impl_decodable_for_uint!(u16, 16);
 impl_decodable_for_uint!(u32, 32);
 impl_decodable_for_uint!(u64, 64);
+
+#[cfg(target_pointer_width = "32")]
+impl_decodable_for_uint!(usize, 32);
+
+#[cfg(target_pointer_width = "64")]
 impl_decodable_for_uint!(usize, 64);
 
 impl Decode for bool {
diff --git a/eth2/utils/ssz/src/lib.rs b/eth2/utils/ssz/src/lib.rs
index fceebcc444..51bafa95ef 100644
--- a/eth2/utils/ssz/src/lib.rs
+++ b/eth2/utils/ssz/src/lib.rs
@@ -46,6 +46,8 @@ pub use encode::{Encode, SszEncoder};
 /// The number of bytes used to represent an offset.
 pub const BYTES_PER_LENGTH_OFFSET: usize = 4;
 /// The maximum value that can be represented using `BYTES_PER_LENGTH_OFFSET`.
+// allows overflow on 32-bit target
+#[allow(const_err)]
 pub const MAX_LENGTH_VALUE: usize = (1 << (BYTES_PER_LENGTH_OFFSET * 8)) - 1;
 
 /// Convenience function to SSZ encode an object supporting ssz::Encode.