diff --git a/hash-db/Cargo.toml b/hash-db/Cargo.toml
index d0c6f104..0e60cf91 100644
--- a/hash-db/Cargo.toml
+++ b/hash-db/Cargo.toml
@@ -7,8 +7,3 @@ license = "Apache-2.0"
 categories = [ "no-std" ]
 repository = "https://github.com/paritytech/trie"
 edition = "2018"
-
-[features]
-default = ["std"]
-std = [
-]
diff --git a/hash-db/src/lib.rs b/hash-db/src/lib.rs
index 2ffd7d82..b9f5f30a 100644
--- a/hash-db/src/lib.rs
+++ b/hash-db/src/lib.rs
@@ -14,23 +14,13 @@
 
 //! Database of byte-slices keyed to their hash.
 
-#![cfg_attr(not(feature = "std"), no_std)]
+#![no_std]
 
-#[cfg(not(feature = "std"))]
 use core::hash;
-#[cfg(feature = "std")]
-use std::fmt::Debug;
-#[cfg(feature = "std")]
-use std::hash;
+use core::fmt::Debug;
 
-#[cfg(feature = "std")]
 pub trait MaybeDebug: Debug {}
-#[cfg(feature = "std")]
 impl<T: Debug> MaybeDebug for T {}
-#[cfg(not(feature = "std"))]
-pub trait MaybeDebug {}
-#[cfg(not(feature = "std"))]
-impl<T> MaybeDebug for T {}
 
 /// A trie node prefix, it is the nibble path from the trie root
 /// to the trie node.
@@ -205,7 +195,6 @@ impl<'a, H: Hasher, T> AsHashDB<H, T> for &'a mut dyn HashDB<H, T> {
 	}
 }
 
-#[cfg(feature = "std")]
 impl<'a, K, V> AsPlainDB<K, V> for &'a mut dyn PlainDB<K, V> {
 	fn as_plain_db(&self) -> &dyn PlainDB<K, V> {
 		&**self
diff --git a/memory-db/Cargo.toml b/memory-db/Cargo.toml
index b8913a26..459e3c5e 100644
--- a/memory-db/Cargo.toml
+++ b/memory-db/Cargo.toml
@@ -18,9 +18,7 @@ criterion = "0.5.1"
 
 [features]
 default = ["std"]
-std = [
-  "hash-db/std",
-]
+std = []
 
 [[bench]]
 name = "bench"
diff --git a/test-support/keccak-hasher/Cargo.toml b/test-support/keccak-hasher/Cargo.toml
index d933d44d..1408d542 100644
--- a/test-support/keccak-hasher/Cargo.toml
+++ b/test-support/keccak-hasher/Cargo.toml
@@ -14,6 +14,4 @@ hash256-std-hasher = { path = "../../hash256-std-hasher", version = "0.15.2" }
 
 [features]
 default = ["std"]
-std = [
-  "hash-db/std",
-]
+std = []
diff --git a/trie-db/Cargo.toml b/trie-db/Cargo.toml
index 6b029fcb..3973db4e 100644
--- a/trie-db/Cargo.toml
+++ b/trie-db/Cargo.toml
@@ -16,6 +16,5 @@ rustc-hex = { version = "2.1.0", default-features = false, optional = true }
 [features]
 default = ["std"]
 std = [
-  "hash-db/std",
   "rustc-hex",
 ]
diff --git a/trie-eip1186/Cargo.toml b/trie-eip1186/Cargo.toml
index 0179f638..8ca97dcd 100644
--- a/trie-eip1186/Cargo.toml
+++ b/trie-eip1186/Cargo.toml
@@ -15,5 +15,4 @@ hash-db = { path = "../hash-db", default-features = false, version = "0.16.0"}
 default = ["std"]
 std = [
   "trie-db/std",
-  "hash-db/std",
 ]
diff --git a/trie-root/Cargo.toml b/trie-root/Cargo.toml
index 7a39bddd..9eb2da7e 100644
--- a/trie-root/Cargo.toml
+++ b/trie-root/Cargo.toml
@@ -13,6 +13,4 @@ hash-db = { path = "../hash-db", default-features = false, version = "0.16.0" }
 
 [features]
 default = ["std"]
-std = [
-	"hash-db/std"
-]
+std = []