diff --git a/proto/backend.proto b/proto/backend.proto
index 6a4fb91dc..ad16f6bed 100644
--- a/proto/backend.proto
+++ b/proto/backend.proto
@@ -385,14 +385,14 @@ message Card {
     sint32 usn = 6;
     uint32 ctype = 7;
     sint32 queue = 8;
-    int64 due = 9;
-    int64 ivl = 10;
+    sint32 due = 9;
+    uint32 ivl = 10;
     uint32 factor = 11;
-    int64 reps = 12;
-    int64 lapses = 13;
-    int64 left = 14;
-    int64 odue = 15;
+    uint32 reps = 12;
+    uint32 lapses = 13;
+    uint32 left = 14;
+    sint32 odue = 15;
     int64 odid = 16;
-    int64 flags = 17;
+    uint32 flags = 17;
     string data = 18;
 }
diff --git a/pylib/anki/cards.py b/pylib/anki/cards.py
index 823d8f1de..d3887410c 100644
--- a/pylib/anki/cards.py
+++ b/pylib/anki/cards.py
@@ -82,28 +82,23 @@ class Card:
         self.flags = c.flags
         self.data = c.data
 
-    def _preFlush(self) -> None:
-        hooks.card_will_flush(self)
-        self.mod = intTime()
-        self.usn = self.col.usn()
-        # bug check
+    def _bugcheck(self) -> None:
         if (
             self.queue == QUEUE_TYPE_REV
             and self.odue
             and not self.col.decks.isDyn(self.did)
         ):
             hooks.card_odue_was_invalid()
-        assert self.due < 4294967296
 
     def flush(self) -> None:
-        self._preFlush()
+        self._bugcheck()
+        hooks.card_will_flush(self)
+        # mtime & usn are set by backend
         card = BackendCard(
             id=self.id,
             nid=self.nid,
             did=self.did,
             ord=self.ord,
-            mtime=self.mod,
-            usn=self.usn,
             ctype=self.type,
             queue=self.queue,
             due=self.due,
diff --git a/rslib/src/backend/mod.rs b/rslib/src/backend/mod.rs
index 66282c5fc..81a71c266 100644
--- a/rslib/src/backend/mod.rs
+++ b/rslib/src/backend/mod.rs
@@ -637,8 +637,8 @@ impl Backend {
     }
 
     fn update_card(&self, pbcard: pb::Card) -> Result<()> {
-        let card = pbcard_to_native(pbcard)?;
-        self.with_col(|col| col.with_ctx(|ctx| ctx.storage.update_card(&card)))
+        let mut card = pbcard_to_native(pbcard)?;
+        self.with_col(|col| col.with_ctx(|ctx| ctx.update_card(&mut card)))
     }
 }
 
@@ -751,7 +751,7 @@ fn card_to_pb(c: Card) -> pb::Card {
         left: c.left,
         odue: c.odue,
         odid: c.odid.0,
-        flags: c.flags,
+        flags: c.flags as u32,
         data: c.data,
     }
 }
@@ -778,7 +778,7 @@ fn pbcard_to_native(c: pb::Card) -> Result<Card> {
         left: c.left,
         odue: c.odue,
         odid: DeckID(c.odid),
-        flags: c.flags,
+        flags: c.flags as u8,
         data: c.data,
     })
 }
diff --git a/rslib/src/card.rs b/rslib/src/card.rs
index d1267fc87..05bd3d857 100644
--- a/rslib/src/card.rs
+++ b/rslib/src/card.rs
@@ -3,8 +3,9 @@
 
 use crate::decks::DeckID;
 use crate::define_newtype;
+use crate::err::Result;
 use crate::notes::NoteID;
-use crate::{timestamp::TimestampSecs, types::Usn};
+use crate::{collection::RequestContext, timestamp::TimestampSecs, types::Usn};
 use num_enum::TryFromPrimitive;
 use serde_repr::{Deserialize_repr, Serialize_repr};
 
@@ -48,15 +49,15 @@ pub struct Card {
     pub(crate) usn: Usn,
     pub(crate) ctype: CardType,
     pub(crate) queue: CardQueue,
-    pub(crate) due: i64,
-    pub(crate) ivl: i64,
+    pub(crate) due: i32,
+    pub(crate) ivl: u32,
     pub(crate) factor: u16,
-    pub(crate) reps: i64,
-    pub(crate) lapses: i64,
-    pub(crate) left: i64,
-    pub(crate) odue: i64,
+    pub(crate) reps: u32,
+    pub(crate) lapses: u32,
+    pub(crate) left: u32,
+    pub(crate) odue: i32,
     pub(crate) odid: DeckID,
-    pub(crate) flags: i64,
+    pub(crate) flags: u8,
     pub(crate) data: String,
 }
 
@@ -84,3 +85,11 @@ impl Default for Card {
         }
     }
 }
+
+impl RequestContext<'_> {
+    pub fn update_card(&mut self, card: &mut Card) -> Result<()> {
+        card.mtime = TimestampSecs::now();
+        card.usn = self.storage.usn()?;
+        self.storage.update_card(card)
+    }
+}
diff --git a/rslib/src/storage/sqlite.rs b/rslib/src/storage/sqlite.rs
index a3bb4caf0..b57a3fd4f 100644
--- a/rslib/src/storage/sqlite.rs
+++ b/rslib/src/storage/sqlite.rs
@@ -215,9 +215,7 @@ impl SqliteStorage {
 
 pub(crate) struct StorageContext<'a> {
     pub(crate) db: &'a Connection,
-    #[allow(dead_code)]
     server: bool,
-    #[allow(dead_code)]
     usn: Option<Usn>,
 
     timing_today: Option<SchedTimingToday>,
@@ -303,7 +301,6 @@ impl StorageContext<'_> {
         Ok(())
     }
 
-    #[allow(dead_code)]
     pub(crate) fn usn(&mut self) -> Result<Usn> {
         if self.server {
             if self.usn.is_none() {
@@ -313,7 +310,7 @@ impl StorageContext<'_> {
                         .query_row(NO_PARAMS, |row| row.get(0))?,
                 );
             }
-            Ok(*self.usn.as_ref().unwrap())
+            Ok(self.usn.clone().unwrap())
         } else {
             Ok(Usn(-1))
         }