diff --git a/bin/stateless-guest/Cargo.lock b/bin/stateless-guest/Cargo.lock
index d04a42535..1809aff88 100644
--- a/bin/stateless-guest/Cargo.lock
+++ b/bin/stateless-guest/Cargo.lock
@@ -2501,6 +2501,15 @@ dependencies = [
  "syn 2.0.118",
 ]
 
+[[package]]
+name = "openvm-bigint-guest"
+version = "2.0.0"
+source = "git+https://github.com/openvm-org/openvm.git?branch=develop-v2.1.0#1417e1f11c5578a2fa364e8553f3923ee498fbf8"
+dependencies = [
+ "openvm-platform",
+ "strum_macros 0.26.4",
+]
+
 [[package]]
 name = "openvm-chainspec"
 version = "0.4.0"
@@ -2754,6 +2763,7 @@ version = "0.4.0"
 dependencies = [
  "openvm",
  "openvm-algebra-guest",
+ "openvm-bigint-guest",
  "openvm-ecc-guest",
  "openvm-stateless-executor",
 ]
@@ -3823,8 +3833,7 @@ dependencies = [
 [[package]]
 name = "ruint"
 version = "1.19.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "45caf26f647c19115bf9c453c70ffe4a4a3a6390dceebd942610584f99b8ddce"
+source = "git+https://github.com/Qumeric/uint?rev=cf03e356e38133ad27ee72644e0c4ef7c8e6433e#cf03e356e38133ad27ee72644e0c4ef7c8e6433e"
 dependencies = [
  "alloy-rlp",
  "ark-ff 0.3.0",
@@ -3852,8 +3861,7 @@ dependencies = [
 [[package]]
 name = "ruint-macro"
 version = "1.2.1"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "48fd7bd8a6377e15ad9d42a8ec25371b94ddc67abe7c8b9127bec79bebaaae18"
+source = "git+https://github.com/Qumeric/uint?rev=cf03e356e38133ad27ee72644e0c4ef7c8e6433e#cf03e356e38133ad27ee72644e0c4ef7c8e6433e"
 
 [[package]]
 name = "rustc-hash"
diff --git a/bin/stateless-guest/Cargo.toml b/bin/stateless-guest/Cargo.toml
index 0b4cf8229..8fcd9d520 100644
--- a/bin/stateless-guest/Cargo.toml
+++ b/bin/stateless-guest/Cargo.toml
@@ -13,6 +13,9 @@ openvm-stateless-executor = { path = "../../crates/stateless-executor", default-
 openvm = { git = "https://github.com/openvm-org/openvm.git", branch = "develop-v2.1.0", default-features = false, features = ["getrandom-unsupported"] }
 openvm-algebra-guest = { git = "https://github.com/openvm-org/openvm.git", branch = "develop-v2.1.0", optional = true }
 openvm-ecc-guest = { git = "https://github.com/openvm-org/openvm.git", branch = "develop-v2.1.0", optional = true }
+# Defines the 256-bit instruction shims that the patched `ruint` below calls. Nothing here
+# references it directly; it is linked in to provide those symbols.
+openvm-bigint-guest = { git = "https://github.com/openvm-org/openvm.git", branch = "develop-v2.1.0", features = ["export-intrinsics"] }
 
 # Enable std feature for host builds (provides critical-section implementation)
 [target.'cfg(not(any(target_os = "none", target_os = "openvm")))'.dependencies]
@@ -21,6 +24,12 @@ openvm-stateless-executor = { path = "../../crates/stateless-executor", default-
 [package.metadata.cargo-machete]
 ignored = ["openvm-algebra-guest", "openvm-ecc-guest"]
 
+# `ruint`'s 256-bit multiply, shifts and comparison each become a single OpenVM instruction
+# instead of a limb loop. Only this workspace is patched, because only the guest has the
+# instructions; host builds keep the released crate.
+[patch.crates-io]
+ruint = { git = "https://github.com/Qumeric/uint", rev = "cf03e356e38133ad27ee72644e0c4ef7c8e6433e" }
+
 [lints.rust]
 unexpected_cfgs = { level = "warn", check-cfg = [
     'cfg(openvm_intrinsics)',
diff --git a/bin/stateless-guest/src/main.rs b/bin/stateless-guest/src/main.rs
index 3b75b5aea..b5efd01a7 100644
--- a/bin/stateless-guest/src/main.rs
+++ b/bin/stateless-guest/src/main.rs
@@ -5,6 +5,9 @@
 #![cfg_attr(not(feature = "std"), no_std)]
 
 use openvm::io::{read, reveal_bytes32};
+// Linked for the 256-bit instruction shims it exports, which `ruint` calls. Without a reference
+// the rlib is dropped before those symbols reach the link.
+use openvm_bigint_guest as _;
 use openvm_stateless_executor::{io::StatelessExecutorInput, ChainVariant, StatelessExecutor};
 
 openvm::entry!(main);