diff --git a/cozo-core/src/data/functions.rs b/cozo-core/src/data/functions.rs
index b36009f1..ef328d3f 100644
--- a/cozo-core/src/data/functions.rs
+++ b/cozo-core/src/data/functions.rs
@@ -14,7 +14,7 @@ use std::time::{SystemTime, UNIX_EPOCH};
 
 use chrono::{DateTime, TimeZone, Utc};
 use itertools::Itertools;
-#[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+#[cfg(target_arch = "wasm32")]
 use js_sys::Date;
 use miette::{bail, ensure, miette, Result};
 use num_traits::FloatConst;
@@ -1486,13 +1486,13 @@ pub(crate) fn op_to_uuid(args: &[DataValue]) -> Result<DataValue> {
 }
 
 define_op!(OP_NOW, 0, false);
-#[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+#[cfg(target_arch = "wasm32")]
 pub(crate) fn op_now(_args: &[DataValue]) -> Result<DataValue> {
     let d: f64 = Date::now() / 1000.;
     Ok(DataValue::from(d))
 }
 
-#[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+#[cfg(not(target_arch = "wasm32"))]
 pub(crate) fn op_now(_args: &[DataValue]) -> Result<DataValue> {
     let now = SystemTime::now();
     Ok(DataValue::from(
@@ -1501,12 +1501,12 @@ pub(crate) fn op_now(_args: &[DataValue]) -> Result<DataValue> {
 }
 
 pub(crate) fn current_validity() -> ValidityTs {
-    #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+    #[cfg(not(target_arch = "wasm32"))]
     let ts_micros = {
         let now = SystemTime::now();
         now.duration_since(UNIX_EPOCH).unwrap().as_micros() as i64
     };
-    #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+    #[cfg(target_arch = "wasm32")]
     let ts_micros = { (Date::now() * 1000.) as i64 };
 
     ValidityTs(Reverse(ts_micros))
@@ -1575,14 +1575,14 @@ define_op!(OP_RAND_UUID_V1, 0, false);
 pub(crate) fn op_rand_uuid_v1(_args: &[DataValue]) -> Result<DataValue> {
     let mut rng = rand::thread_rng();
     let uuid_ctx = uuid::v1::Context::new(rng.gen());
-    #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+    #[cfg(target_arch = "wasm32")]
     let ts = {
         let since_epoch: f64 = Date::now();
         let seconds = since_epoch.floor();
         let fractional = (since_epoch - seconds) * 1.0e9;
         Timestamp::from_unix(uuid_ctx, seconds as u64, fractional as u32)
     };
-    #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+    #[cfg(not(target_arch = "wasm32"))]
     let ts = {
         let now = SystemTime::now();
         let since_epoch = now.duration_since(UNIX_EPOCH).unwrap();
diff --git a/cozo-core/src/lib.rs b/cozo-core/src/lib.rs
index 3b351c0f..ba1b2946 100644
--- a/cozo-core/src/lib.rs
+++ b/cozo-core/src/lib.rs
@@ -173,17 +173,17 @@ impl DbInstance {
         payload: &str,
         params: BTreeMap<String, JsonValue>,
     ) -> JsonValue {
-        #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+        #[cfg(not(target_arch = "wasm32"))]
         let start = Instant::now();
 
         match self.run_script(payload, params) {
             Ok(named_rows) => {
                 let mut j_val = named_rows.into_json();
-                #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+                #[cfg(not(target_arch = "wasm32"))]
                 let took = start.elapsed().as_secs_f64();
                 let map = j_val.as_object_mut().unwrap();
                 map.insert("ok".to_string(), json!(true));
-                #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+                #[cfg(not(target_arch = "wasm32"))]
                 map.insert("took".to_string(), json!(took));
 
                 j_val
diff --git a/cozo-core/src/parse/query.rs b/cozo-core/src/parse/query.rs
index 161f46fe..bb2157d2 100644
--- a/cozo-core/src/parse/query.rs
+++ b/cozo-core/src/parse/query.rs
@@ -245,10 +245,10 @@ pub(crate) fn parse_query(
                 out_opts.timeout = Some(timeout);
             }
             Rule::sleep_option => {
-                #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+                #[cfg(target_arch = "wasm32")]
                 bail!(":sleep is not supported under WASM");
 
-                #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+                #[cfg(not(target_arch = "wasm32"))]
                 {
                     let pair = pair.into_inner().next().unwrap();
                     let span = pair.extract_span();
diff --git a/cozo-core/src/query/eval.rs b/cozo-core/src/query/eval.rs
index 44de3021..515f5423 100644
--- a/cozo-core/src/query/eval.rs
+++ b/cozo-core/src/query/eval.rs
@@ -13,7 +13,7 @@ use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering};
 use itertools::Itertools;
 use log::{debug, trace};
 use miette::Result;
-#[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+#[cfg(not(target_arch = "wasm32"))]
 use rayon::prelude::*;
 
 use crate::data::aggr::Aggregation;
@@ -178,7 +178,7 @@ impl<'a> SessionTx<'a> {
                     };
                     Ok((k, new_store))
                 };
-                #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+                #[cfg(not(target_arch = "wasm32"))]
                 {
                     let limiter_enabled = limiter.total.is_some();
                     for res in prog
@@ -203,7 +203,7 @@ impl<'a> SessionTx<'a> {
                         to_merge.insert(k, new_store);
                     }
                 }
-                #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+                #[cfg(target_arch = "wasm32")]
                 {
                     for res in prog.iter().map(execution) {
                         let (k, new_store) = res?;
@@ -251,7 +251,7 @@ impl<'a> SessionTx<'a> {
                     };
                     Ok((k, new_store))
                 };
-                #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+                #[cfg(not(target_arch = "wasm32"))]
                 {
                     let limiter_enabled = limiter.total.is_some();
                     // entry rules with limiter must execute sequentially in order to get deterministic ordering
@@ -276,7 +276,7 @@ impl<'a> SessionTx<'a> {
                         to_merge.insert(k, new_store);
                     }
                 }
-                #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+                #[cfg(target_arch = "wasm32")]
                 {
                     for res in prog.iter().map(execution) {
                         let (k, new_store) = res?;
diff --git a/cozo-core/src/runtime/db.rs b/cozo-core/src/runtime/db.rs
index 5cef4e48..787c8411 100644
--- a/cozo-core/src/runtime/db.rs
+++ b/cozo-core/src/runtime/db.rs
@@ -532,7 +532,7 @@ impl<'s, S: Storage<'s>> Db<S> {
                         }
                         res = q_res;
                         cleanups.extend(q_cleanups);
-                        #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+                        #[cfg(not(target_arch = "wasm32"))]
                         if let Some(secs) = sleep_opt {
                             thread::sleep(Duration::from_micros((secs * 1000000.) as u64));
                         }
@@ -903,15 +903,15 @@ impl<'s, S: Storage<'s>> Db<S> {
         let id = self.queries_count.fetch_add(1, Ordering::AcqRel);
 
         // time the query
-        #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+        #[cfg(not(target_arch = "wasm32"))]
         let now = SystemTime::now();
-        #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+        #[cfg(not(target_arch = "wasm32"))]
         let since_the_epoch = now
             .duration_since(UNIX_EPOCH)
             .into_diagnostic()?
             .as_secs_f64();
 
-        #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+        #[cfg(target_arch = "wasm32")]
         let since_the_epoch = js_sys::Date::now();
 
         let handle = RunningQueryHandle {
@@ -1195,11 +1195,11 @@ impl Poison {
         }
         Ok(())
     }
-    #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+    #[cfg(target_arch = "wasm32")]
     pub(crate) fn set_timeout(&self, _secs: f64) -> Result<()> {
         bail!("Cannot set timeout when threading is disallowed");
     }
-    #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+    #[cfg(not(target_arch = "wasm32"))]
     pub(crate) fn set_timeout(&self, secs: f64) -> Result<()> {
         let pill = self.clone();
         thread::spawn(move || {
diff --git a/cozo-core/src/storage/mem.rs b/cozo-core/src/storage/mem.rs
index 6af0fa0d..a949e4e3 100644
--- a/cozo-core/src/storage/mem.rs
+++ b/cozo-core/src/storage/mem.rs
@@ -73,9 +73,9 @@ impl<'s> Storage<'s> for MemStorage {
                 wtr.remove(k);
             }
         };
-        #[cfg(all(target_arch = "wasm32", target_os = "unknown"))]
+        #[cfg(target_arch = "wasm32")]
         closure();
-        #[cfg(not(all(target_arch = "wasm32", target_os = "unknown")))]
+        #[cfg(not(target_arch = "wasm32"))]
         std::thread::spawn(closure);
         Ok(())
     }