diff --git a/.github/workflows/ci-linux.yml b/.github/workflows/ci-linux.yml
index 5298db53..c4284a32 100644
--- a/.github/workflows/ci-linux.yml
+++ b/.github/workflows/ci-linux.yml
@@ -12,6 +12,8 @@ jobs:
       run: |
         sudo apt-get update
         sudo apt-get install -y flatpak flatpak-builder
+    - name: Update Rust
+      run: rustup update stable
     - name: Add additional Rust targets
       run: rustup target add x86_64-unknown-none
     - name: Lint Rust sources
diff --git a/src/core/src/vmm/aarch64.rs b/src/core/src/vmm/aarch64.rs
index 690f0729..37ba570e 100644
--- a/src/core/src/vmm/aarch64.rs
+++ b/src/core/src/vmm/aarch64.rs
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: MIT OR Apache-2.0
 use super::hv::{Cpu, CpuStates};
 use super::hw::RamMap;
 use super::MainCpuError;
@@ -8,7 +9,7 @@ pub fn setup_main_cpu(cpu: &mut impl Cpu, entry: usize, map: RamMap) -> Result<(
         .states()
         .map_err(|e| MainCpuError::GetCpuStatesFailed(Box::new(e)))?;
     let mmfr0 = states
-        .get_id_aa64_mmfr0()
+        .get_id_aa64mmfr0()
         .map_err(|e| MainCpuError::GetIdAa64mmfr0Failed(Box::new(e)))?;
 
     match map.page_size.get() {
@@ -20,6 +21,13 @@ pub fn setup_main_cpu(cpu: &mut impl Cpu, entry: usize, map: RamMap) -> Result<(
         _ => todo!(),
     }
 
+    // Check if CPU support at least 36 bits physical address.
+    let pa_range = mmfr0 & 0xF;
+
+    if pa_range == 0 {
+        return Err(MainCpuError::PhysicalAddressTooSmall);
+    }
+
     // Set PSTATE so the PE run in AArch64 mode. Not sure why we need M here since the document said
     // it is ignore. See https://gist.github.com/imbushuo/51b09e61ecd7b7ac063853ad65cedf34 where
     // M = 5 came from.
diff --git a/src/core/src/vmm/hv/macos/cpu.rs b/src/core/src/vmm/hv/macos/cpu.rs
index 2adb39c6..8c4d5ca7 100644
--- a/src/core/src/vmm/hv/macos/cpu.rs
+++ b/src/core/src/vmm/hv/macos/cpu.rs
@@ -14,6 +14,7 @@ type hv_vcpu_t = hv_sys::hv_vcpu_t;
 #[allow(non_camel_case_types)]
 type hv_vcpu_t = hv_sys::hv_vcpuid_t;
 
+#[cfg(target_arch = "x86_64")]
 macro_rules! wrap_return {
     ($ret:expr) => {
         match NonZero::new($ret) {
@@ -129,7 +130,7 @@ impl<'a> Cpu for HfCpu<'a> {
     fn states(&mut self) -> Result<Self::States<'_>, Self::GetStatesErr> {
         Ok(HfStates {
             cpu: self,
-            id_aa64_mmfr0: State::None,
+            id_aa64mmfr0: State::None,
             pstate: State::None,
             sctlr_el1: State::None,
             mair_el1: State::None,
@@ -190,7 +191,7 @@ impl<'a> Drop for HfCpu<'a> {
 pub struct HfStates<'a, 'b> {
     cpu: &'a mut HfCpu<'b>,
     #[cfg(target_arch = "aarch64")]
-    id_aa64_mmfr0: State<u64>,
+    id_aa64mmfr0: State<u64>,
     #[cfg(target_arch = "x86_64")]
     rsp: State<usize>,
     #[cfg(target_arch = "x86_64")]
@@ -237,16 +238,16 @@ impl<'a, 'b> CpuStates for HfStates<'a, 'b> {
     type Err = StatesError;
 
     #[cfg(target_arch = "aarch64")]
-    fn get_id_aa64_mmfr0(&mut self) -> Result<u64, Self::Err> {
+    fn get_id_aa64mmfr0(&mut self) -> Result<u64, Self::Err> {
         use hv_sys::hv_sys_reg_t_HV_SYS_REG_ID_AA64MMFR0_EL1 as HV_SYS_REG_ID_AA64MMFR0_EL1;
 
-        let v = match self.id_aa64_mmfr0 {
+        let v = match self.id_aa64mmfr0 {
             State::None => {
                 let v = self
                     .cpu
                     .read_sys(HV_SYS_REG_ID_AA64MMFR0_EL1)
                     .map_err(StatesError::ReadRegisterFailed)?;
-                self.id_aa64_mmfr0 = State::Clean(v);
+                self.id_aa64mmfr0 = State::Clean(v);
                 v
             }
             State::Clean(v) | State::Dirty(v) => v,
diff --git a/src/core/src/vmm/hv/mod.rs b/src/core/src/vmm/hv/mod.rs
index b3873c4c..ae5b1ec9 100644
--- a/src/core/src/vmm/hv/mod.rs
+++ b/src/core/src/vmm/hv/mod.rs
@@ -59,7 +59,7 @@ pub trait CpuStates {
     type Err: Error + Send + 'static;
 
     #[cfg(target_arch = "aarch64")]
-    fn get_id_aa64_mmfr0(&mut self) -> Result<u64, Self::Err>;
+    fn get_id_aa64mmfr0(&mut self) -> Result<u64, Self::Err>;
 
     #[cfg(target_arch = "x86_64")]
     fn set_rdi(&mut self, v: usize);
diff --git a/src/core/src/vmm/mod.rs b/src/core/src/vmm/mod.rs
index c1334c5a..2bf4f73e 100644
--- a/src/core/src/vmm/mod.rs
+++ b/src/core/src/vmm/mod.rs
@@ -744,6 +744,10 @@ enum MainCpuError {
     #[error("vCPU does not support {0:#x} page size")]
     PageSizeNotSupported(NonZero<usize>),
 
+    #[cfg(target_arch = "aarch64")]
+    #[error("physical address supported by vCPU too small")]
+    PhysicalAddressTooSmall,
+
     #[error("couldn't commit vCPU states")]
     CommitCpuStatesFailed(#[source] Box<dyn Error + Send>),
 }
diff --git a/src/obkrnl/src/main.rs b/src/obkrnl/src/main.rs
index b5ac6a6f..f8be4dbf 100644
--- a/src/obkrnl/src/main.rs
+++ b/src/obkrnl/src/main.rs
@@ -5,7 +5,6 @@ use crate::config::set_boot_env;
 use crate::context::Context;
 use crate::malloc::KernelHeap;
 use crate::proc::Thread;
-use alloc::string::String;
 use alloc::sync::Arc;
 use core::arch::asm;
 use core::mem::zeroed;
@@ -82,16 +81,8 @@ fn panic(i: &PanicInfo) -> ! {
         None => ("unknown", 0),
     };
 
-    // Get message.
-    let msg = if let Some(&v) = i.payload().downcast_ref::<&str>() {
-        v
-    } else if let Some(v) = i.payload().downcast_ref::<String>() {
-        v
-    } else {
-        "unknown panic payload"
-    };
-
-    crate::console::error(file, line, msg);
+    // Print the message.
+    crate::console::error(file, line, i.message());
     crate::panic::panic();
 }