diff --git a/grub-core/kern/ieee1275/init.c b/grub-core/kern/ieee1275/init.c
index ef55107467..6a51c9efab 100644
--- a/grub-core/kern/ieee1275/init.c
+++ b/grub-core/kern/ieee1275/init.c
@@ -311,6 +311,18 @@ struct option_vector2 {
   grub_uint8_t max_pft_size;
 } __attribute__((packed));
 
+struct option_vector5 {
+        grub_uint8_t byte1;
+        grub_uint8_t byte2;
+        grub_uint8_t byte3;
+        grub_uint8_t cmo;
+        grub_uint8_t associativity;
+        grub_uint8_t bin_opts;
+        grub_uint8_t micro_checkpoint;
+        grub_uint8_t reserved0;
+        grub_uint32_t max_cpus;
+} __attribute__((packed));
+
 struct pvr_entry {
   grub_uint32_t mask;
   grub_uint32_t entry;
@@ -329,6 +341,8 @@ struct cas_vector {
   grub_uint16_t vec3;
   grub_uint8_t vec4_size;
   grub_uint16_t vec4;
+  grub_uint8_t vec5_size;
+  struct option_vector5 vec5;
 } __attribute__((packed));
 
 /* Call ibm,client-architecture-support to try to get more RMA.
@@ -349,7 +363,7 @@ grub_ieee1275_ibm_cas (void)
   } args;
   struct cas_vector vector = {
     .pvr_list = { { 0x00000000, 0xffffffff } }, /* any processor */
-    .num_vecs = 4 - 1,
+    .num_vecs = 5 - 1,
     .vec1_size = 0,
     .vec1 = 0x80, /* ignore */
     .vec2_size = 1 + sizeof(struct option_vector2) - 2,
@@ -360,6 +374,10 @@ grub_ieee1275_ibm_cas (void)
     .vec3 = 0x00e0, // ask for FP + VMX + DFP but don't halt if unsatisfied
     .vec4_size = 2 - 1,
     .vec4 = 0x0001, // set required minimum capacity % to the lowest value
+    .vec5_size = 1 + sizeof(struct option_vector5) - 2,
+    .vec5 = {
+	0, 0, 0, 0, 0, 0, 0, 0, 256
+    }
   };
 
   INIT_IEEE1275_COMMON (&args.common, "call-method", 3, 2);