diff --git a/grub-core/kern/ieee1275/init.c b/grub-core/kern/ieee1275/init.c
index dfbd0b899..a5586f85b 100644
--- a/grub-core/kern/ieee1275/init.c
+++ b/grub-core/kern/ieee1275/init.c
@@ -780,7 +780,7 @@ struct cas_vector
 
 /*
  * Call ibm,client-architecture-support to try to get more RMA.
- * We ask for 512MB which should be enough to verify a distro kernel.
+ * We ask for 768MB which should be enough to verify a distro kernel.
  * We ignore most errors: if we don't succeed we'll proceed with whatever
  * memory we have.
  */
@@ -852,7 +852,7 @@ grub_ieee1275_ibm_cas (void)
     .vec1 = 0x80, /* ignore */
     .vec2_size = 1 + sizeof (struct option_vector2) - 2,
     .vec2 = {
-      0, 0, -1, -1, -1, -1, -1, 512, -1, 0, 48
+      0, 0, -1, -1, -1, -1, -1, 768, -1, 0, 48
     },
     .vec3_size = 2 - 1,
     .vec3 = 0x00e0, /* ask for FP + VMX + DFP but don't halt if unsatisfied */
@@ -889,6 +889,10 @@ grub_claim_heap (void)
 {
   grub_err_t err;
   grub_uint32_t total = HEAP_MAX_SIZE;
+#if defined(__powerpc__)
+  grub_uint32_t ibm_ca_support_reboot = 0;
+  grub_ssize_t actual;
+#endif
 
   err = grub_ieee1275_total_mem (&rmo_top);
 
@@ -901,11 +905,49 @@ grub_claim_heap (void)
     grub_mm_add_region_fn = grub_ieee1275_mm_add_region;
 
 #if defined(__powerpc__)
+  /* Check if it's a CAS reboot with below property. If so, we will skip CAS call. */
+  if (grub_ieee1275_get_integer_property (grub_ieee1275_chosen,
+                                          "ibm,client-architecture-support-reboot",
+                                          &ibm_ca_support_reboot,
+                                          sizeof (ibm_ca_support_reboot),
+                                          &actual) >= 0)
+    grub_dprintf ("ieee1275", "ibm,client-architecture-support-reboot: %" PRIuGRUB_UINT32_T "\n",
+                  ibm_ca_support_reboot);
+
   if (grub_ieee1275_test_flag (GRUB_IEEE1275_FLAG_CAN_TRY_CAS_FOR_MORE_MEMORY))
     {
-      /* if we have an error, don't call CAS, just hope for the best */
-      if (err == GRUB_ERR_NONE && rmo_top < (512 * 1024 * 1024))
-	grub_ieee1275_ibm_cas ();
+      /*
+       * If we have an error don't call CAS. Just hope for the best.
+       * Along with the above, if the rmo_top is 512 MB or above. We
+       * will skip the CAS call. However, if we call CAS, the rmo_top
+       * will be set to 768 MB via CAS Vector2. But we need to call
+       * CAS with rmo_top < 512 MB to avoid the issue on the older
+       * Linux kernel, which still uses rmo_top as 512 MB. If we call
+       * CAS with a condition rmo_top < 768 MB, it will result in an
+       * issue due to the IBM CAS reboot feature and we won't be able
+       * to boot the newer kernel. Whenever a reboot is detected as
+       * the CAS reboot by GRUB it will boot the machine with the
+       * last booted kernel by reading the variable boot-last-label
+       * which has the info related to the last boot and it's specific
+       * to IBM PowerPC. Due to this, the machine will boot with the
+       * last booted kernel which has rmo_top as 512 MB. Also, if the
+       * reboot is detected as a CAS reboot, the GRUB will skip the CAS
+       * call. As the CAS has already been called earlier, so it is
+       * not required to call CAS even if the other conditions are met.
+       * This condition will also prevent a scenario where the machine
+       * get stuck in the CAS reboot loop while booting a machine with
+       * an older kernel, having option_vector2 MIN_RMA as 512 MB in
+       * Linux prom_init.c and GRUB uses rmo_top < 768 MB condition
+       * for calling CAS. Due to their respective conditions, Linux
+       * CAS and GRUB CAS will keep doing the CAS calls and change
+       * the MIN_RMA from 768, changed by GRUB, to 512, changed by Linux,
+       * to 768, changed by GRUB, to 512, changed by Linux, and so on.
+       * The machine will stuck in this CAS reboot loop forever.
+       *
+       * IBM PAPR: https://openpower.foundation/specifications/linuxonpower/
+       */
+      if (!ibm_ca_support_reboot && err == GRUB_ERR_NONE && rmo_top < (512 * 1024 * 1024))
+        grub_ieee1275_ibm_cas ();
     }
 #endif