diff --git a/drivers/src/imsic/core.rs b/drivers/src/imsic/core.rs
index 34a85389..ae414e48 100644
--- a/drivers/src/imsic/core.rs
+++ b/drivers/src/imsic/core.rs
@@ -357,16 +357,16 @@ impl Imsic {
             // Each MMIO region must map the start of a group.
             let location = geometry
                 .addr_to_location(region_base_addr)
-                .ok_or_else(|| Error::InvalidMmioRegion(region_base_addr.bits()))?;
-            if location.hart().bits() != 0 || location.file().bits() != 0 {
+                .ok_or_else(|| Error::InvalidMmioRegionLocation(region_base_addr.bits()))?;
+            if location.file().bits() != 0 {
                 return Err(Error::InvalidMmioRegion(region_base_addr.bits()));
             }
             // Unwrap ok, we've guaranteed there are an even number of `reg` cells.
             let region_size = regs.next().unwrap();
-            if region_size % per_hart_size != 0 {
-                return Err(Error::MisalignedMmioRegion(region_base_addr.bits()));
+            if region_size < guests_per_hart as u64 * PageSize::Size4k as u64 {
+                return Err(Error::MmioRegionTooSmall(region_size));
             }
-            let harts_in_region = region_size / per_hart_size;
+            let harts_in_region = core::cmp::max(region_size / per_hart_size, 1);
 
             for i in 0..harts_in_region {
                 // Each 'interrupts-extended' property is of the from "<phandle> <interrupt-id>".
diff --git a/drivers/src/imsic/error.rs b/drivers/src/imsic/error.rs
index 225e0c96..d197f3fc 100644
--- a/drivers/src/imsic/error.rs
+++ b/drivers/src/imsic/error.rs
@@ -27,6 +27,8 @@ pub enum Error {
     MisalignedMmioRegion(u64),
     /// An MMIO region specified in the device tree did not match the expected pattern.
     InvalidMmioRegion(u64),
+    /// Regions doesn't map to a hart-stride aligned address.
+    InvalidMmioRegionLocation(u64),
     /// Invalid parent interrupt specification in the device tree.
     InvalidParentInterrupt(u32, u32),
     /// The given CPU does not have a valid IMSIC location specified in the device tree.
@@ -37,6 +39,8 @@ pub enum Error {
     TooManyInterruptFiles,
     /// There were fewer interrupt files than CPUs found in the device tree.
     MissingInterruptFiles,
+    /// An imsic reg regions was specified that is too small to hold the guest files.
+    MmioRegionTooSmall(u64),
     /// Failed to add an MMIO region to the system memory map.
     AddingMmioRegion(page_tracking::MemMapError),
     /// The requested CPU does not exist.
diff --git a/page-tracking/src/page_info.rs b/page-tracking/src/page_info.rs
index bf58a231..6957ad6b 100644
--- a/page-tracking/src/page_info.rs
+++ b/page-tracking/src/page_info.rs
@@ -488,7 +488,7 @@ impl PageMap {
         let page_map_region = mem_map
             .regions()
             .find(|r| r.region_type() == HwMemRegionType::Available && r.size() >= page_map_size)
-            .ok_or(PageTrackingError::PageMapNoSpace)?;
+            .ok_or(PageTrackingError::PageMapNoSpace(page_map_size))?;
 
         let page_map_base = page_map_region.base();
 
diff --git a/page-tracking/src/page_tracker.rs b/page-tracking/src/page_tracker.rs
index 1b385664..ca5e2dd7 100644
--- a/page-tracking/src/page_tracker.rs
+++ b/page-tracking/src/page_tracker.rs
@@ -66,7 +66,7 @@ pub enum Error {
     /// Failed to reserve region for page map
     PageMapReserveRegion(hw_mem_map::Error),
     /// No memory available for page map
-    PageMapNoSpace,
+    PageMapNoSpace(u64),
 }
 
 /// Holds the result of page tracking operations.
diff --git a/src/main.rs b/src/main.rs
index c571c21c..aff1b190 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -359,7 +359,6 @@ enum RequiredDeviceProbe {
     Imsic(drivers::imsic::ImsicError),
     Pci(drivers::pci::PciError),
     Reset(drivers::reset::Error),
-    Uart(drivers::uart::Error),
 }
 
 impl Display for RequiredDeviceProbe {
@@ -369,7 +368,6 @@ impl Display for RequiredDeviceProbe {
             Imsic(e) => write!(f, "IMSIC: {:?}", e),
             Pci(e) => write!(f, "PCI: {:?}", e),
             Reset(e) => write!(f, "Reset: {:?}", e),
-            Uart(e) => write!(f, "UART: {:?}", e),
         }
     }
 }
@@ -478,8 +476,9 @@ fn primary_init(hart_id: u64, fdt_addr: u64) -> Result<CpuParams, Error> {
     let hyp_dt = DeviceTree::from(&hyp_fdt).map_err(Error::FdtCreation)?;
 
     // Find the UART and switch to it as the system console.
-    UartDriver::probe_from(&hyp_dt, &mut mem_map)
-        .map_err(|e| Error::RequiredDeviceProbe(RequiredDeviceProbe::Uart(e)))?;
+    if let Err(e) = UartDriver::probe_from(&hyp_dt, &mut mem_map) {
+        println!("Failed to probe UART: {:?}", e);
+    }
 
     // Discover the CPU topology.
     CpuInfo::parse_from(&hyp_dt).map_err(Error::CpuTopologyGeneration)?;