diff --git a/Cargo.lock b/Cargo.lock
index 1bf2f99..b8ad073 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -27,9 +27,8 @@ dependencies = [
 
 [[package]]
 name = "amplify"
-version = "4.7.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "7147b742325842988dd6c793d55f58df3ae36bccf7d9b6e07db10ab035be343d"
+version = "4.7.1"
+source = "git+https://github.com/rust-amplify/rust-amplify?branch=v4.0#8108ed0ed906b699072b07eeb7e8a959ed0e62e5"
 dependencies = [
  "amplify_apfloat",
  "amplify_derive",
diff --git a/Cargo.toml b/Cargo.toml
index 5f80930..7c3a61f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -21,7 +21,7 @@ name = "aluvm-stl"
 required-features = ["stl"]
 
 [dependencies]
-amplify = { version = "4.7.0", default-features = false, features = ["apfloat", "derive", "hex"] }
+amplify = { version = "4.7.1", default-features = false, features = ["apfloat", "derive", "hex"] }
 ascii-armor = { version = "0.7.2", optional = true }
 baid64 = "0.2.2"
 paste = "1"
@@ -39,7 +39,7 @@ serde_crate = { package = "serde", version = "1", optional = true }
 default = ["std"]
 all = ["stl", "std", "log", "secp256k1", "curve25519", "serde", "ascii-armor"]
 stl = ["strict_types/armor", "std"]
-std = ["amplify/std"]
+std = ["amplify/std", "alloc"]
 log = ["std"]
 alloc = ["amplify/alloc"]
 curve25519 = ["curve25519-dalek"]
@@ -55,3 +55,6 @@ wasm-bindgen-test = "0.3"
 
 [package.metadata.docs.rs]
 features = ["all"]
+
+[patch.crates-io]
+amplify = { git = "https://github.com/rust-amplify/rust-amplify", branch = "v4.0" }
diff --git a/src/data/byte_str.rs b/src/data/byte_str.rs
index 585e2b3..0dcd9bc 100644
--- a/src/data/byte_str.rs
+++ b/src/data/byte_str.rs
@@ -23,9 +23,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::boxed::Box;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 use core::borrow::{Borrow, BorrowMut};
 use core::convert::TryFrom;
diff --git a/src/data/number.rs b/src/data/number.rs
index 0aea924..6f4f565 100644
--- a/src/data/number.rs
+++ b/src/data/number.rs
@@ -26,9 +26,9 @@
 //! Module defining number layout (integer, signed/unsigned, float etc) and universal in-memory
 //! number representation.
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::format;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::string::{String, ToString};
 use core::fmt::{
     self, Debug, Display, Formatter, LowerExp, LowerHex, Octal, UpperExp, UpperHex, Write,
diff --git a/src/isa/bytecode.rs b/src/isa/bytecode.rs
index fd3d868..580cc2e 100644
--- a/src/isa/bytecode.rs
+++ b/src/isa/bytecode.rs
@@ -25,7 +25,7 @@
 
 //! Instruction serialization and deserialization from bytecode.
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::boxed::Box;
 use core::ops::RangeInclusive;
 
diff --git a/src/isa/exec.rs b/src/isa/exec.rs
index 2dfb077..d25bf5f 100644
--- a/src/isa/exec.rs
+++ b/src/isa/exec.rs
@@ -23,10 +23,10 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::boxed::Box;
 use alloc::collections::BTreeSet;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::string::{String, ToString};
 use core::cmp::Ordering;
 use core::ops::{BitAnd, BitOr, BitXor, Neg, Rem, Shl, Shr};
diff --git a/src/isa/flags.rs b/src/isa/flags.rs
index 121c2a8..7b334b3 100644
--- a/src/isa/flags.rs
+++ b/src/isa/flags.rs
@@ -25,9 +25,9 @@
 
 //! Flags used by operation codes
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::borrow::ToOwned;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::string::String;
 use core::fmt::{self, Display, Formatter, Write};
 use core::str::FromStr;
diff --git a/src/isa/instr.rs b/src/isa/instr.rs
index a4f8083..19b91bd 100644
--- a/src/isa/instr.rs
+++ b/src/isa/instr.rs
@@ -23,7 +23,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::boxed::Box;
 
 use super::{
diff --git a/src/lib.rs b/src/lib.rs
index 279b4eb..f8205e2 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -142,10 +142,11 @@
 // TODO(#7) Complete assembly compiler for string operations
 // TODO(#8) Implement operations on Edwards curves
 
+#[cfg(not(any(feature = "alloc", feature = "std")))]
+compile_error!("either `alloc` or `std` feature must be used");
+
 #[macro_use]
 extern crate alloc;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
-extern crate alloc as std;
 
 #[macro_use]
 extern crate amplify;
diff --git a/src/library/lib.rs b/src/library/lib.rs
index 49b2ec8..9dafaf7 100644
--- a/src/library/lib.rs
+++ b/src/library/lib.rs
@@ -23,9 +23,9 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::string::{String, ToString};
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 use core::cmp::Ordering;
 use core::fmt::{self, Display, Formatter};
diff --git a/src/library/segs.rs b/src/library/segs.rs
index 0d2a0d5..17c07fc 100644
--- a/src/library/segs.rs
+++ b/src/library/segs.rs
@@ -25,12 +25,12 @@
 
 //! Data structures representing static library segments
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::borrow::ToOwned;
 use alloc::collections::{btree_set, BTreeSet};
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::string::{String, ToString};
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 use core::fmt::{self, Debug, Display, Formatter};
 use core::str::FromStr;
diff --git a/src/reg/core_regs.rs b/src/reg/core_regs.rs
index b9e5319..dd52e68 100644
--- a/src/reg/core_regs.rs
+++ b/src/reg/core_regs.rs
@@ -23,11 +23,11 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::boxed::Box;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::string::ToString;
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::vec::Vec;
 use core::fmt::{self, Debug, Formatter};
 
diff --git a/src/vm.rs b/src/vm.rs
index 46a24cb..75dd3cf 100644
--- a/src/vm.rs
+++ b/src/vm.rs
@@ -25,7 +25,7 @@
 
 //! Alu virtual machine
 
-#[cfg(all(feature = "alloc", not(feature = "std")))]
+#[cfg(feature = "alloc")]
 use alloc::boxed::Box;
 use core::marker::PhantomData;