diff --git a/crates/xenia-app/tests/golden/sylpheed_n50m.json b/crates/xenia-app/tests/golden/sylpheed_n50m.json
index 552dc43..f3d5ba1 100644
--- a/crates/xenia-app/tests/golden/sylpheed_n50m.json
+++ b/crates/xenia-app/tests/golden/sylpheed_n50m.json
@@ -1,10 +1,10 @@
 {
-  "instructions": 50000003,
-  "imports": 451508,
+  "instructions": 50000001,
+  "imports": 451499,
   "unimpl": 0,
-  "draws": 0,
-  "swaps": 2,
-  "unique_render_targets": 0,
-  "shader_blobs_live": 0,
+  "draws": 78,
+  "swaps": 3,
+  "unique_render_targets": 2,
+  "shader_blobs_live": 3,
   "texture_cache_entries": 0
 }
diff --git a/crates/xenia-gpu/src/gpu_system.rs b/crates/xenia-gpu/src/gpu_system.rs
index bf27114..fbc5bd7 100644
--- a/crates/xenia-gpu/src/gpu_system.rs
+++ b/crates/xenia-gpu/src/gpu_system.rs
@@ -603,14 +603,21 @@ impl GpuSystem {
     /// Release.
     pub fn sync_with_mmio(&mut self) {
         let wptr_dwords = self.mmio.cp_rb_wptr.load(Ordering::Acquire);
-        if wptr_dwords != self.ring.write_offset_dwords && self.ring.size_dwords != 0 {
-            self.ring.write_offset_dwords = wptr_dwords % self.ring.size_dwords;
+        // CP_RB_WPTR governs ONLY the primary ring. While an indirect buffer
+        // is executing, the active `self.ring` is a fixed linear sub-stream
+        // and the primary ring is saved at the bottom of the IB stack —
+        // applying the (primary) write pointer to the IB would corrupt its
+        // extent (e.g. `wptr % ib_size`) and strand the GPU mid-buffer.
+        let primary = self.ib_stack.first_mut().unwrap_or(&mut self.ring);
+        if wptr_dwords != primary.write_offset_dwords && primary.size_dwords != 0 {
+            primary.write_offset_dwords = wptr_dwords % primary.size_dwords;
         }
-        // Mirror our read pointer (Release pairs with any guest-side
+        let primary_rptr = primary.read_offset_dwords;
+        // Mirror the *primary* read pointer (Release pairs with any guest-side
         // Acquire-load of CP_RB_RPTR for ring writeback bookkeeping).
         self.mmio
             .cp_rb_rptr
-            .store(self.ring.read_offset_dwords, Ordering::Release);
+            .store(primary_rptr, Ordering::Release);
     }
 
     /// True iff `execute_one` is expected to make progress without blocking.
@@ -618,7 +625,11 @@ impl GpuSystem {
         if let Some(block) = &self.pending_block {
             return block.is_satisfied(mem, &self.register_file);
         }
-        self.ring.has_pending()
+        // Pending work may be in the active ring OR in a saved caller ring
+        // further down the IB stack (an exhausted IB still needs `execute_one`
+        // to pop back and resume the primary ring, whose WPTR may have since
+        // advanced).
+        self.ring.has_pending() || self.ib_stack.iter().any(|r| r.has_pending())
     }
 
     /// Execute exactly one PM4 packet. Returns [`ExecOutcome::Idle`] when
@@ -730,13 +741,21 @@ impl GpuSystem {
 
     /// Called by `VdInitializeRingBuffer` to give us the primary ring.
     pub fn initialize_ring_buffer(&mut self, base: u32, size_log2: u32) {
-        let size_bytes = 1u32 << size_log2.min(31);
+        // Canary `CommandProcessor::InitializeRingBuffer` (command_processor.cc:
+        // 436): `primary_buffer_size_ = 1 << (size_log2 + 3)` *bytes*. The
+        // `VdInitializeRingBuffer` `r4` argument is log2(size-in-quadwords),
+        // so the byte size is `1 << (size_log2 + 3)` (× 8 bytes/quadword), i.e.
+        // `1 << (size_log2 + 1)` dwords. (Sylpheed passes size_log2=12 →
+        // 32768 bytes / 8192 dwords; the previous `1 << size_log2` undersized
+        // the ring 8× and desynced WPTR wrap math from the guest.)
+        let size_bytes = 1u32 << size_log2.saturating_add(3).min(31);
         // The guest hands us a bare *physical* ring base; project it onto the
         // committed backing window so ring reads hit real PM4 packets (see
         // `physical_to_backing`).
         let base = physical_to_backing(base);
         self.ring.base = base;
         self.ring.size_dwords = size_bytes / 4;
+        self.ring.indirect = false;
         self.ring.read_offset_dwords = 0;
         // `write_offset` is driven by the guest — start at 0 so the ring
         // appears empty until MMIO writes advance it.
@@ -935,6 +954,10 @@ impl GpuSystem {
                     write_offset_dwords: ib_size, // IB is fully-written at jump time
                     rptr_writeback_addr: 0,
                     rptr_writeback_block_dwords: 0,
+                    // Linear sub-stream: drain [0, ib_size) then pop. Never
+                    // wraps, and `sync_with_mmio`'s CP_RB_WPTR must not touch
+                    // it (canary executes IBs through a separate reader).
+                    indirect: true,
                 };
                 tracing::debug!(
                     ib_ptr = format_args!("{ib_ptr:#010x}"),
diff --git a/crates/xenia-gpu/src/ring_view.rs b/crates/xenia-gpu/src/ring_view.rs
index a164d73..df8bf64 100644
--- a/crates/xenia-gpu/src/ring_view.rs
+++ b/crates/xenia-gpu/src/ring_view.rs
@@ -32,6 +32,16 @@ pub struct RingBufferView {
     /// `VdEnableRingBufferRPtrWriteBack`). We always write back eagerly, so
     /// we don't actually use this for scheduling — kept for observability.
     pub rptr_writeback_block_dwords: u32,
+    /// True for an indirect-buffer (`INDIRECT_BUFFER`) view. An IB is a fixed
+    /// *linear* sub-stream, not a circular ring: it is fully written when the
+    /// GPU jumps to it, so the read pointer advances monotonically from `0` to
+    /// `size_dwords` and then the buffer is exhausted (the caller ring is
+    /// popped). It must NOT wrap, and the primary `CP_RB_WPTR` must not be
+    /// applied to it. Mirrors canary `ExecuteIndirectBuffer`, which executes
+    /// the IB through a separate `RingBuffer reader_` and restores the primary
+    /// reader afterward (command_processor.cc). Circular (primary-ring)
+    /// semantics are used when this is `false`.
+    pub indirect: bool,
 }
 
 impl RingBufferView {
@@ -46,7 +56,16 @@ impl RingBufferView {
 
     /// True if there is pending unread data to consume.
     pub fn has_pending(&self) -> bool {
-        self.is_initialized() && self.read_offset_dwords != self.write_offset_dwords
+        if !self.is_initialized() {
+            return false;
+        }
+        if self.indirect {
+            // Linear sub-stream: exhausted once the read pointer reaches the
+            // (fixed) write pointer. Never wraps.
+            self.read_offset_dwords < self.write_offset_dwords
+        } else {
+            self.read_offset_dwords != self.write_offset_dwords
+        }
     }
 
     /// Number of dwords we can consume without wrapping past the write ptr.
@@ -54,7 +73,10 @@ impl RingBufferView {
         if !self.is_initialized() {
             return 0;
         }
-        if self.write_offset_dwords >= self.read_offset_dwords {
+        if self.indirect {
+            self.write_offset_dwords
+                .saturating_sub(self.read_offset_dwords)
+        } else if self.write_offset_dwords >= self.read_offset_dwords {
             self.write_offset_dwords - self.read_offset_dwords
         } else {
             // write has wrapped — we can read up to the end of the ring.
@@ -62,13 +84,19 @@ impl RingBufferView {
         }
     }
 
-    /// Advance the read pointer by `dwords`, wrapping at `size_dwords`.
+    /// Advance the read pointer by `dwords`. Circular rings wrap at
+    /// `size_dwords`; an indirect buffer advances linearly (no wrap) so it
+    /// terminates exactly at its fixed write pointer.
     pub fn advance_read(&mut self, dwords: u32) {
         if self.size_dwords == 0 {
             return;
         }
-        self.read_offset_dwords =
-            (self.read_offset_dwords + dwords) % self.size_dwords;
+        if self.indirect {
+            self.read_offset_dwords = self.read_offset_dwords.saturating_add(dwords);
+        } else {
+            self.read_offset_dwords =
+                (self.read_offset_dwords + dwords) % self.size_dwords;
+        }
     }
 
     /// Guest address for the dword at relative offset `i` from the current
@@ -77,7 +105,11 @@ impl RingBufferView {
         if !self.is_initialized() {
             return None;
         }
-        let off = (self.read_offset_dwords + offset_dwords) % self.size_dwords;
+        let off = if self.indirect {
+            self.read_offset_dwords.saturating_add(offset_dwords)
+        } else {
+            (self.read_offset_dwords + offset_dwords) % self.size_dwords
+        };
         Some(self.base.wrapping_add(off.wrapping_mul(4)))
     }
 }
@@ -120,4 +152,52 @@ mod tests {
         assert_eq!(v.addr_at_offset(1), Some(0x4000_0000));
         assert_eq!(v.addr_at_offset(2), Some(0x4000_0004));
     }
+
+    #[test]
+    fn indirect_buffer_drains_linearly_and_terminates() {
+        // An indirect buffer is a fixed linear sub-stream: read advances from
+        // 0 to `size_dwords` and then is exhausted — it must NOT wrap back to
+        // 0 (which previously caused an infinite re-read of a system command
+        // buffer; iterate-2O). write_offset == size, exactly as the
+        // INDIRECT_BUFFER handler sets it.
+        let mut ib = RingBufferView {
+            base: 0x4adf_5080,
+            size_dwords: 11,
+            read_offset_dwords: 0,
+            write_offset_dwords: 11,
+            rptr_writeback_addr: 0,
+            rptr_writeback_block_dwords: 0,
+            indirect: true,
+        };
+        assert!(ib.has_pending());
+        // Drain the exact packet layout observed for Sylpheed's init IB:
+        // 2 + 3 + 6 dwords = 11.
+        ib.advance_read(2);
+        assert!(ib.has_pending());
+        ib.advance_read(3);
+        assert!(ib.has_pending());
+        ib.advance_read(6); // reaches 11 == write
+        assert_eq!(ib.read_offset_dwords, 11);
+        assert!(
+            !ib.has_pending(),
+            "indirect buffer must terminate at write ptr, not wrap to 0"
+        );
+        // addr_at_offset must not modulo-wrap for an indirect buffer.
+        ib.read_offset_dwords = 9;
+        assert_eq!(ib.addr_at_offset(1), Some(0x4adf_5080 + 10 * 4));
+    }
+
+    #[test]
+    fn indirect_flag_does_not_affect_circular_ring() {
+        // Sanity: a circular (primary) ring still wraps as before.
+        let mut v = RingBufferView::new();
+        v.base = 0x4adc_c000;
+        v.size_dwords = 8192;
+        v.read_offset_dwords = 8190;
+        v.write_offset_dwords = 2;
+        assert!(v.has_pending());
+        v.advance_read(4); // (8190 + 4) % 8192 = 2
+        assert_eq!(v.read_offset_dwords, 2);
+        assert!(!v.has_pending());
+    }
 }
diff --git a/crates/xenia-kernel/src/exports.rs b/crates/xenia-kernel/src/exports.rs
index e118e57..7632cf1 100644
--- a/crates/xenia-kernel/src/exports.rs
+++ b/crates/xenia-kernel/src/exports.rs
@@ -2883,10 +2883,12 @@ fn vd_initialize_ring_buffer(ctx: &mut PpcContext, _mem: &GuestMemory, state: &m
     // packets directly into ring memory at the current WPTR (the GPU
     // backend lives on a worker thread under `--gpu-thread` so we can't
     // read its `ring.base` from the kernel side without a channel hop).
-    // Per canary: size_log2 is log2(size in BYTES), so size in dwords =
-    // 2^size_log2 / 4 = 1 << (size_log2 - 2).
+    // Per canary `CommandProcessor::InitializeRingBuffer`: the ring is
+    // `1 << (size_log2 + 3)` bytes = `1 << (size_log2 + 1)` dwords (`r4` is
+    // log2 of the size in quadwords). Kept in sync with
+    // `GpuSystem::initialize_ring_buffer`. (Currently bookkeeping-only.)
     state.ring_base = ptr;
-    state.ring_size_dwords = if size_log2 >= 2 { 1u32 << (size_log2 - 2) } else { 0 };
+    state.ring_size_dwords = 1u32 << (size_log2 + 1);
     ctx.gpr[3] = 0;
 }