diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index fa13fce355..7e9f7d146d 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -189,7 +189,7 @@ static void arm_cpu_reset(DeviceState *dev)
 
     if (arm_feature(env, ARM_FEATURE_AARCH64)) {
         /* 64 bit CPUs always start in 64 bit mode */
-        env->aarch64 = 1;
+        env->aarch64 = true;
 #if defined(CONFIG_USER_ONLY)
         env->pstate = PSTATE_MODE_EL0t;
         /* Userspace expects access to DC ZVA, CTL_EL0 and the cache ops */
diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index bee1cf4653..31e4670927 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -259,7 +259,7 @@ typedef struct CPUArchState {
      *  all other bits are stored in their correct places in env->pstate
      */
     uint32_t pstate;
-    uint32_t aarch64; /* 1 if CPU is in aarch64 state; inverse of PSTATE.nRW */
+    bool aarch64; /* True if CPU is in aarch64 state; inverse of PSTATE.nRW */
 
     /* Cached TBFLAGS state.  See below for which bits are included.  */
     CPUARMTBFlags hflags;
diff --git a/target/arm/helper-a64.c b/target/arm/helper-a64.c
index 7cf953b1e6..77a8502b6b 100644
--- a/target/arm/helper-a64.c
+++ b/target/arm/helper-a64.c
@@ -952,7 +952,7 @@ void HELPER(exception_return)(CPUARMState *env, uint64_t new_pc)
     qemu_mutex_unlock_iothread();
 
     if (!return_to_aa64) {
-        env->aarch64 = 0;
+        env->aarch64 = false;
         /* We do a raw CPSR write because aarch64_sync_64_to_32()
          * will sort the register banks out for us, and we've already
          * caught all the bad-mode cases in el_from_spsr().
@@ -975,7 +975,7 @@ void HELPER(exception_return)(CPUARMState *env, uint64_t new_pc)
     } else {
         int tbii;
 
-        env->aarch64 = 1;
+        env->aarch64 = true;
         spsr &= aarch64_pstate_valid_mask(&env_archcpu(env)->isar);
         pstate_write(env, spsr);
         if (!arm_singlestep_active(env)) {
diff --git a/target/arm/helper.c b/target/arm/helper.c
index d7715c911a..f1e91b197e 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -10181,7 +10181,7 @@ static void arm_cpu_do_interrupt_aarch64(CPUState *cs)
     }
 
     pstate_write(env, PSTATE_DAIF | new_mode);
-    env->aarch64 = 1;
+    env->aarch64 = true;
     aarch64_restore_sp(env, new_el);
     helper_rebuild_hflags_a64(env, new_el);
 
diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index 567e296b21..b11a8b9a18 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -564,7 +564,7 @@ int hvf_arch_init_vcpu(CPUState *cpu)
     hv_return_t ret;
     int i;
 
-    env->aarch64 = 1;
+    env->aarch64 = true;
     asm volatile("mrs %0, cntfrq_el0" : "=r"(arm_cpu->gt_cntfrq_hz));
 
     /* Allocate enough space for our sysreg sync */