diff --git a/target/hppa/cpu.h b/target/hppa/cpu.h
index 743fc90e14..22690e351d 100644
--- a/target/hppa/cpu.h
+++ b/target/hppa/cpu.h
@@ -210,15 +210,15 @@ typedef struct CPUArchState {
     target_ureg cr_back[2];  /* back of cr17/cr18 */
     target_ureg shadow[7];   /* shadow registers */
 
-    /* ??? The number of entries isn't specified by the architecture.  */
-#ifdef TARGET_HPPA64
-#define HPPA_BTLB_FIXED         0       /* BTLBs are not supported in 64-bit machines */
-#else
-#define HPPA_BTLB_FIXED         16
-#endif
-#define HPPA_BTLB_VARIABLE      0
+    /*
+     * ??? The number of entries isn't specified by the architecture.
+     * BTLBs are not supported in 64-bit machines.
+     */
+#define PA10_BTLB_FIXED         16
+#define PA10_BTLB_VARIABLE      0
+#define HPPA_BTLB_ENTRIES(E)    (env_archcpu(E)->is_pa20 ? 0 \
+                                 : PA10_BTLB_FIXED + PA10_BTLB_VARIABLE)
 #define HPPA_TLB_ENTRIES        256
-#define HPPA_BTLB_ENTRIES       (HPPA_BTLB_FIXED + HPPA_BTLB_VARIABLE)
 
     /* ??? Implement a unified itlb/dtlb for the moment.  */
     /* ??? We should use a more intelligent data structure.  */
diff --git a/hw/hppa/machine.c b/hw/hppa/machine.c
index cf28cb9586..07f8ebeb6a 100644
--- a/hw/hppa/machine.c
+++ b/hw/hppa/machine.c
@@ -133,7 +133,7 @@ static FWCfgState *create_fw_cfg(MachineState *ms)
     fw_cfg_add_file(fw_cfg, "/etc/firmware-min-version",
                     g_memdup(&val, sizeof(val)), sizeof(val));
 
-    val = cpu_to_le64(HPPA_TLB_ENTRIES - HPPA_BTLB_ENTRIES);
+    val = cpu_to_le64(HPPA_TLB_ENTRIES - HPPA_BTLB_ENTRIES(&cpu[0]->env));
     fw_cfg_add_file(fw_cfg, "/etc/cpu/tlb_entries",
                     g_memdup(&val, sizeof(val)), sizeof(val));
 
@@ -429,10 +429,6 @@ static void hppa_machine_reset(MachineState *ms, ShutdownCause reason)
 
         cs->exception_index = -1;
         cs->halted = 0;
-
-        /* clear any existing TLB and BTLB entries */
-        memset(cpu[i]->env.tlb, 0, sizeof(cpu[i]->env.tlb));
-        cpu[i]->env.tlb_last = HPPA_BTLB_ENTRIES;
     }
 
     /* already initialized by machine_hppa_init()? */
diff --git a/target/hppa/cpu.c b/target/hppa/cpu.c
index ed5b6afd10..41abdb04d0 100644
--- a/target/hppa/cpu.c
+++ b/target/hppa/cpu.c
@@ -139,6 +139,9 @@ static void hppa_cpu_realizefn(DeviceState *dev, Error **errp)
         HPPACPU *cpu = HPPA_CPU(cs);
         cpu->alarm_timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                         hppa_cpu_alarm_timer, cpu);
+
+        memset(cpu->env.tlb, 0, sizeof(cpu->env.tlb));
+        cpu->env.tlb_last = HPPA_BTLB_ENTRIES(&cpu->env);
     }
 #endif
 }
diff --git a/target/hppa/mem_helper.c b/target/hppa/mem_helper.c
index 350485f619..b2a75f6408 100644
--- a/target/hppa/mem_helper.c
+++ b/target/hppa/mem_helper.c
@@ -57,7 +57,7 @@ static void hppa_flush_tlb_ent(CPUHPPAState *env, hppa_tlb_entry *ent,
                                 HPPA_MMU_FLUSH_MASK, TARGET_LONG_BITS);
 
     /* never clear BTLBs, unless forced to do so. */
-    if (ent < &env->tlb[HPPA_BTLB_ENTRIES] && !force_flush_btlb) {
+    if (ent < &env->tlb[HPPA_BTLB_ENTRIES(env)] && !force_flush_btlb) {
         return;
     }
 
@@ -68,11 +68,11 @@ static void hppa_flush_tlb_ent(CPUHPPAState *env, hppa_tlb_entry *ent,
 static hppa_tlb_entry *hppa_alloc_tlb_ent(CPUHPPAState *env)
 {
     hppa_tlb_entry *ent;
-    uint32_t i;
+    uint32_t i, btlb_entries = HPPA_BTLB_ENTRIES(env);
 
-    if (env->tlb_last < HPPA_BTLB_ENTRIES || env->tlb_last >= ARRAY_SIZE(env->tlb)) {
-        i = HPPA_BTLB_ENTRIES;
-        env->tlb_last = HPPA_BTLB_ENTRIES + 1;
+    if (env->tlb_last < btlb_entries || env->tlb_last >= ARRAY_SIZE(env->tlb)) {
+        i = btlb_entries;
+        env->tlb_last = btlb_entries + 1;
     } else {
         i = env->tlb_last;
         env->tlb_last++;
@@ -279,7 +279,7 @@ void HELPER(itlba)(CPUHPPAState *env, target_ulong addr, target_ureg reg)
     int i;
 
     /* Zap any old entries covering ADDR; notice empty entries on the way.  */
-    for (i = HPPA_BTLB_ENTRIES; i < ARRAY_SIZE(env->tlb); ++i) {
+    for (i = HPPA_BTLB_ENTRIES(env); i < ARRAY_SIZE(env->tlb); ++i) {
         hppa_tlb_entry *ent = &env->tlb[i];
         if (ent->va_b <= addr && addr <= ent->va_e) {
             if (ent->entry_valid) {
@@ -363,11 +363,13 @@ void HELPER(ptlb)(CPUHPPAState *env, target_ulong addr)
    number of pages/entries (we choose all), and is local to the cpu.  */
 void HELPER(ptlbe)(CPUHPPAState *env)
 {
+    uint32_t btlb_entries = HPPA_BTLB_ENTRIES(env);
+
     trace_hppa_tlb_ptlbe(env);
     qemu_log_mask(CPU_LOG_MMU, "FLUSH ALL TLB ENTRIES\n");
-    memset(&env->tlb[HPPA_BTLB_ENTRIES], 0,
-        sizeof(env->tlb) - HPPA_BTLB_ENTRIES * sizeof(env->tlb[0]));
-    env->tlb_last = HPPA_BTLB_ENTRIES;
+    memset(&env->tlb[btlb_entries], 0,
+           sizeof(env->tlb) - btlb_entries * sizeof(env->tlb[0]));
+    env->tlb_last = btlb_entries;
     tlb_flush_by_mmuidx(env_cpu(env), HPPA_MMU_FLUSH_MASK);
 }
 
@@ -427,13 +429,16 @@ void HELPER(diag_btlb)(CPUHPPAState *env)
     hppa_tlb_entry *btlb;
     uint64_t virt_page;
     uint32_t *vaddr;
+    uint32_t btlb_entries;
 
-#ifdef TARGET_HPPA64
     /* BTLBs are not supported on 64-bit CPUs */
-    env->gr[28] = -1; /* nonexistent procedure */
-    return;
-#endif
+    if (env_archcpu(env)->is_pa20) {
+        env->gr[28] = -1; /* nonexistent procedure */
+        return;
+    }
+
     env->gr[28] = 0; /* PDC_OK */
+    btlb_entries = HPPA_BTLB_ENTRIES(env);
 
     switch (env->gr[25]) {
     case 0:
@@ -446,8 +451,8 @@ void HELPER(diag_btlb)(CPUHPPAState *env)
         } else {
             vaddr[0] = cpu_to_be32(1);
             vaddr[1] = cpu_to_be32(16 * 1024);
-            vaddr[2] = cpu_to_be32(HPPA_BTLB_FIXED);
-            vaddr[3] = cpu_to_be32(HPPA_BTLB_VARIABLE);
+            vaddr[2] = cpu_to_be32(PA10_BTLB_FIXED);
+            vaddr[3] = cpu_to_be32(PA10_BTLB_VARIABLE);
         }
         break;
     case 1:
@@ -464,7 +469,7 @@ void HELPER(diag_btlb)(CPUHPPAState *env)
                     (long long) virt_page << TARGET_PAGE_BITS,
                     (long long) (virt_page + len) << TARGET_PAGE_BITS,
                     (long long) virt_page, phys_page, len, slot);
-        if (slot < HPPA_BTLB_ENTRIES) {
+        if (slot < btlb_entries) {
             btlb = &env->tlb[slot];
             /* force flush of possibly existing BTLB entry */
             hppa_flush_tlb_ent(env, btlb, true);
@@ -484,7 +489,7 @@ void HELPER(diag_btlb)(CPUHPPAState *env)
         slot = env->gr[22];
         qemu_log_mask(CPU_LOG_MMU, "PDC_BLOCK_TLB: PDC_BTLB_PURGE slot %d\n",
                                     slot);
-        if (slot < HPPA_BTLB_ENTRIES) {
+        if (slot < btlb_entries) {
             btlb = &env->tlb[slot];
             hppa_flush_tlb_ent(env, btlb, true);
         } else {
@@ -494,7 +499,7 @@ void HELPER(diag_btlb)(CPUHPPAState *env)
     case 3:
         /* Purge all BTLB entries */
         qemu_log_mask(CPU_LOG_MMU, "PDC_BLOCK_TLB: PDC_BTLB_PURGE_ALL\n");
-        for (slot = 0; slot < HPPA_BTLB_ENTRIES; slot++) {
+        for (slot = 0; slot < btlb_entries; slot++) {
             btlb = &env->tlb[slot];
             hppa_flush_tlb_ent(env, btlb, true);
         }
