diff --git a/src/asahi/lib/cmdbuf.xml b/src/asahi/lib/cmdbuf.xml
index 4b2adf24fb7..8ffae47b2d3 100644
--- a/src/asahi/lib/cmdbuf.xml
+++ b/src/asahi/lib/cmdbuf.xml
@@ -458,4 +458,23 @@
     <field name="Local size Z" size="32" start="7:0" type="uint"/>
     <field name="Unk" size="32" start="8:0" type="hex" default="0x60000160"/>
   </struct>
+
+  <!--- The rest of this file is likely software defined by macOS kernel -->
+  <enum name="IOGPU Attachment Type">
+    <value name="Colour" value="0xA"/>
+    <value name="Depth" value="0xC"/>
+  </enum>
+
+  <struct name="IOGPU Attachment" size="24">
+    <field name="Unk 0" start="0:0" size="16" default="0x100" type="hex"/>
+    <field name="Address" start="0:16" size="48" type="address"/>
+    <field name="Type" start="2:16" size="16" type="IOGPU Attachment Type"/>
+    <field name="Unk 1" start="3:0" size="32" type="hex"/>
+    <field name="Unk 2" start="4:0" size="3" type="hex"/>
+    <field name="Bytes per pixel" start="4:3" size="5" type="uint"/>
+    <field name="Unk 3" start="4:16" size="4" type="hex" default="0xC"/>
+    <!-- Percent of total attachment space used for this attachment, expressed
+         in a decimal percentage [0, 100] <field name="Percent" start="5:16" -->
+    <field name="Percent" start="5:16" size="16" type="uint"/>
+  </struct>
 </agxml>
diff --git a/src/gallium/drivers/asahi/magic.c b/src/gallium/drivers/asahi/magic.c
index e09b28798f9..742306d5f8c 100644
--- a/src/gallium/drivers/asahi/magic.c
+++ b/src/gallium/drivers/asahi/magic.c
@@ -2,7 +2,8 @@
 #include "agx_state.h"
 #include "magic.h"
 
-/* magic code lifted from ./demo ... a lot more reveng needed */
+/* The structures managed in this file appear to be software defined (either in
+ * the macOS kernel driver or in the AGX firmware) */
 
 struct cmdbuf {
    uint32_t *map;
@@ -229,13 +230,16 @@ demo_cmdbuf(uint64_t *buf, size_t size,
    EMIT32(cmdbuf, 0x1); // number of attachments (includes depth/stencil) stored to
 
    /* A single attachment follows, depth/stencil have their own attachments */
-   {
-      EMIT64(cmdbuf, 0x100 | (rt0 << 16));
-      EMIT32(cmdbuf, 0xa0000);
-      EMIT32(cmdbuf, 0x4c000000); // 80000000 also observed, and 8c000 and.. offset into the tilebuffer I imagine
-      EMIT32(cmdbuf, 0x0c001d); // C0020  also observed
-      EMIT32(cmdbuf, 0x640000);
+   agx_pack((cmdbuf->map + cmdbuf->offset), IOGPU_ATTACHMENT, cfg) {
+      cfg.address = rt0;
+      cfg.type = AGX_IOGPU_ATTACHMENT_TYPE_COLOUR;
+      cfg.unk_1 = 0x4c000000;
+      cfg.unk_2 = 0x5;
+      cfg.bytes_per_pixel = 3;
+      cfg.percent = 100;
    }
+
+   cmdbuf->offset += (AGX_IOGPU_ATTACHMENT_LENGTH / 4);
 }
 
 static struct agx_map_header