diff --git a/local/recipes/drivers/redox-driver-pci/source/src/bus.rs b/local/recipes/drivers/redox-driver-pci/source/src/bus.rs
index 77b788fa66..ff3d184436 100644
--- a/local/recipes/drivers/redox-driver-pci/source/src/bus.rs
+++ b/local/recipes/drivers/redox-driver-pci/source/src/bus.rs
@@ -50,8 +50,20 @@ impl Bus for PciBus {
             }
 
             let config_path = path.join("config");
-            let config_data = match fs::read(&config_path) {
-                Ok(d) => d,
+            // Read only the 64-byte standard header: everything PciBus
+            // consumes (vendor/device at 0x00, class block at 0x08-0x0B,
+            // subsystem IDs at 0x2C-0x2F) lives there, and larger reads
+            // cross into PCIe extended space which does not exist on
+            // MCFG-less (PCI 3.0 I/O-port fallback) machines.
+            let config_data = match std::fs::File::open(&config_path) {
+                Ok(file) => {
+                    use std::io::Read;
+                    let mut buf = Vec::new();
+                    match file.take(64).read_to_end(&mut buf) {
+                        Ok(_) => buf,
+                        Err(_) => continue,
+                    }
+                }
                 Err(_) => continue,
             };
 
diff --git a/local/sources/base b/local/sources/base
index c72d4247a6..b0e760659c 160000
--- a/local/sources/base
+++ b/local/sources/base
@@ -1 +1 @@
-Subproject commit c72d4247a66a764b0f06fe62d661ced415538ae2
+Subproject commit b0e760659c4c951381e8916dc64dca8a53af584f