diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
index 6785a90c60..dfd352c473 100644
--- a/hw/ppc/spapr.c
+++ b/hw/ppc/spapr.c
@@ -1504,7 +1504,7 @@ static void spapr_machine_reset(void)
         spapr_ovec_cleanup(spapr->ov5_cas);
         spapr->ov5_cas = spapr_ovec_new();
 
-        ppc_set_compat_all(spapr->max_compat_pvr, &error_fatal);
+        ppc_set_compat(first_ppc_cpu, spapr->max_compat_pvr, &error_fatal);
     }
 
     fdt = spapr_build_fdt(spapr, rtas_addr, spapr->rtas_size);
diff --git a/hw/ppc/spapr_rtas.c b/hw/ppc/spapr_rtas.c
index 4bb939d3d1..2b89e1d448 100644
--- a/hw/ppc/spapr_rtas.c
+++ b/hw/ppc/spapr_rtas.c
@@ -163,6 +163,7 @@ static void rtas_start_cpu(PowerPCCPU *cpu_, sPAPRMachineState *spapr,
         CPUState *cs = CPU(cpu);
         CPUPPCState *env = &cpu->env;
         PowerPCCPUClass *pcc = POWERPC_CPU_GET_CLASS(cpu);
+        Error *local_err = NULL;
 
         if (!cs->halted) {
             rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
@@ -174,6 +175,14 @@ static void rtas_start_cpu(PowerPCCPU *cpu_, sPAPRMachineState *spapr,
          * new cpu enters */
         kvm_cpu_synchronize_state(cs);
 
+        /* Set compatibility mode to match existing cpus */
+        ppc_set_compat(cpu, POWERPC_CPU(first_cpu)->compat_pvr, &local_err);
+        if (local_err) {
+            error_report_err(local_err);
+            rtas_st(rets, 0, RTAS_OUT_HW_ERROR);
+            return;
+        }
+
         env->msr = (1ULL << MSR_SF) | (1ULL << MSR_ME);
 
         /* Enable Power-saving mode Exit Cause exceptions for the new CPU */