diff --git a/src/asahi/lib/agx_nir_lower_gs.c b/src/asahi/lib/agx_nir_lower_gs.c
index e2b3352ebf1..c2ca0349948 100644
--- a/src/asahi/lib/agx_nir_lower_gs.c
+++ b/src/asahi/lib/agx_nir_lower_gs.c
@@ -339,31 +339,6 @@ lower_gs_count_instr(nir_builder *b, nir_intrinsic_instr *intr, void *data)
    }
 }
 
-static bool
-lower_prolog_id(nir_builder *b, nir_intrinsic_instr *intr, void *data)
-{
-   b->cursor = nir_before_instr(&intr->instr);
-
-   nir_def *id;
-   if (intr->intrinsic == nir_intrinsic_load_primitive_id)
-      id = load_primitive_id(b);
-   else if (intr->intrinsic == nir_intrinsic_load_instance_id)
-      id = load_instance_id(b);
-   else
-      return false;
-
-   b->cursor = nir_instr_remove(&intr->instr);
-   nir_def_rewrite_uses(&intr->def, id);
-   return true;
-}
-
-bool
-agx_nir_lower_sw_vs_id(nir_shader *s)
-{
-   return nir_shader_intrinsics_pass(s, lower_prolog_id,
-                                     nir_metadata_control_flow, NULL);
-}
-
 static bool
 lower_id(nir_builder *b, nir_intrinsic_instr *intr, void *data)
 {
diff --git a/src/asahi/lib/agx_nir_lower_gs.h b/src/asahi/lib/agx_nir_lower_gs.h
index 0a970d8c70b..bf34bfcbd97 100644
--- a/src/asahi/lib/agx_nir_lower_gs.h
+++ b/src/asahi/lib/agx_nir_lower_gs.h
@@ -24,9 +24,7 @@ struct nir_def *agx_load_per_vertex_input(struct nir_builder *b,
                                           nir_intrinsic_instr *intr,
                                           struct nir_def *vertex);
 
-bool agx_nir_lower_index_buffer(struct nir_shader *s, unsigned index_size_B);
-
-bool agx_nir_lower_sw_vs_id(nir_shader *s);
+bool agx_nir_lower_sw_vs(struct nir_shader *s, unsigned index_size_B);
 
 bool agx_nir_lower_vs_before_gs(struct nir_shader *vs,
                                 const struct nir_shader *libagx,
diff --git a/src/asahi/lib/agx_nir_lower_ia.c b/src/asahi/lib/agx_nir_lower_ia.c
index 89893fc014c..c83bff3f25b 100644
--- a/src/asahi/lib/agx_nir_lower_ia.c
+++ b/src/asahi/lib/agx_nir_lower_ia.c
@@ -22,7 +22,7 @@
 static nir_def *
 load_vertex_id(nir_builder *b, unsigned index_size_B)
 {
-   nir_def *id = nir_load_primitive_id(b);
+   nir_def *id = nir_channel(b, nir_load_global_invocation_id(b, 32), 0);
 
    /* If drawing with an index buffer, pull the vertex ID. Otherwise, the
     * vertex ID is just the index as-is.
@@ -43,21 +43,26 @@ load_vertex_id(nir_builder *b, unsigned index_size_B)
 }
 
 static bool
-lower_vertex_id(nir_builder *b, nir_intrinsic_instr *intr, void *data)
+lower(nir_builder *b, nir_intrinsic_instr *intr, void *data)
 {
-   if (intr->intrinsic != nir_intrinsic_load_vertex_id)
-      return false;
-
    unsigned *index_size_B = data;
-   b->cursor = nir_instr_remove(&intr->instr);
-   assert(intr->def.bit_size == 32);
-   nir_def_rewrite_uses(&intr->def, load_vertex_id(b, *index_size_B));
-   return true;
+   b->cursor = nir_before_instr(&intr->instr);
+
+   if (intr->intrinsic == nir_intrinsic_load_vertex_id) {
+      nir_def_replace(&intr->def, load_vertex_id(b, *index_size_B));
+      return true;
+   } else if (intr->intrinsic == nir_intrinsic_load_instance_id) {
+      nir_def_replace(&intr->def,
+                      nir_channel(b, nir_load_global_invocation_id(b, 32), 1));
+      return true;
+   }
+
+   return false;
 }
 
 bool
-agx_nir_lower_index_buffer(nir_shader *s, unsigned index_size_B)
+agx_nir_lower_sw_vs(nir_shader *s, unsigned index_size_B)
 {
-   return nir_shader_intrinsics_pass(s, lower_vertex_id,
-                                     nir_metadata_control_flow, &index_size_B);
+   return nir_shader_intrinsics_pass(s, lower, nir_metadata_control_flow,
+                                     &index_size_B);
 }
diff --git a/src/asahi/lib/agx_nir_prolog_epilog.c b/src/asahi/lib/agx_nir_prolog_epilog.c
index 6dc74c6fc61..459bde7b80c 100644
--- a/src/asahi/lib/agx_nir_prolog_epilog.c
+++ b/src/asahi/lib/agx_nir_prolog_epilog.c
@@ -169,8 +169,7 @@ agx_nir_vs_prolog(nir_builder *b, const void *key_)
    lower_vbo(b->shader, key->attribs, key->robustness);
 
    if (!key->hw) {
-      agx_nir_lower_index_buffer(b->shader, key->sw_index_size_B);
-      agx_nir_lower_sw_vs_id(b->shader);
+      agx_nir_lower_sw_vs(b->shader, key->sw_index_size_B);
    }
 
    /* Finally, lower uniforms according to our ABI */