diff --git a/crates/scmi/src/devices/common.rs b/crates/scmi/src/devices/common.rs
index b93fa85..ac3a80a 100644
--- a/crates/scmi/src/devices/common.rs
+++ b/crates/scmi/src/devices/common.rs
@@ -10,9 +10,9 @@ use log::debug;
 use thiserror::Error as ThisError;
 
 use crate::scmi::{
-    DeviceResult, MessageId, MessageValue, MessageValues, ProtocolId, ScmiDevice, ScmiDeviceError,
-    MAX_SIMPLE_STRING_LENGTH, SENSOR_AXIS_DESCRIPTION_GET, SENSOR_CONFIG_GET, SENSOR_CONFIG_SET,
-    SENSOR_CONTINUOUS_UPDATE_NOTIFY, SENSOR_DESCRIPTION_GET, SENSOR_PROTOCOL_ID,
+    self, DeviceResult, MessageId, MessageValue, MessageValues, ProtocolId, ScmiDevice,
+    ScmiDeviceError, MAX_SIMPLE_STRING_LENGTH, SENSOR_AXIS_DESCRIPTION_GET, SENSOR_CONFIG_GET,
+    SENSOR_CONFIG_SET, SENSOR_CONTINUOUS_UPDATE_NOTIFY, SENSOR_DESCRIPTION_GET, SENSOR_PROTOCOL_ID,
     SENSOR_READING_GET,
 };
 
@@ -204,13 +204,22 @@ pub trait SensorT: Send {
     }
 
     fn number_of_axes(&self) -> u32 {
-        1
+        0
+    }
+
+    fn format_unit(&self, axis: u32) -> u32 {
+        (self.unit_exponent(axis) as u32 & 0x1F) << 11 | u32::from(self.unit())
     }
 
     fn description_get(&self) -> DeviceResult {
         // Continuous update required by Linux SCMI IIO driver
         let low = 1 << 30;
-        let high = self.number_of_axes() << 16 | 1 << 8;
+        let n_axes = self.number_of_axes();
+        let high = if n_axes > 0 {
+            n_axes << 16 | 1 << 8
+        } else {
+            self.format_unit(0)
+        };
         let name = self.sensor().name.clone();
         let values: MessageValues = vec![
             // attributes low
@@ -223,7 +232,13 @@ pub trait SensorT: Send {
         Ok(values)
     }
 
-    fn axis_unit(&self) -> u32;
+    fn unit(&self) -> u8 {
+        scmi::SENSOR_UNIT_UNSPECIFIED
+    }
+
+    fn unit_exponent(&self, _axis: u32) -> i8 {
+        0
+    }
 
     fn axis_name_prefix(&self) -> String {
         "axis".to_owned()
@@ -242,7 +257,7 @@ pub trait SensorT: Send {
         let mut values = vec![];
         values.push(MessageValue::Unsigned(axis)); // axis id
         values.push(MessageValue::Unsigned(0)); // attributes low
-        values.push(MessageValue::Unsigned(self.axis_unit())); // attributes high
+        values.push(MessageValue::Unsigned(self.format_unit(axis))); // attributes high
 
         // Name in the recommended format, 16 bytes:
         let prefix = self.axis_name_prefix();
diff --git a/crates/scmi/src/devices/fake.rs b/crates/scmi/src/devices/fake.rs
index cc47d63..5cde468 100644
--- a/crates/scmi/src/devices/fake.rs
+++ b/crates/scmi/src/devices/fake.rs
@@ -3,7 +3,7 @@
 
 // Fake sensor
 
-use crate::scmi::{DeviceResult, MessageValue, SENSOR_UNIT_METERS_PER_SECOND_SQUARED};
+use crate::scmi::{self, DeviceResult, MessageValue};
 
 use super::common::{DeviceProperties, MaybeDevice, Sensor, SensorDevice, SensorT};
 
@@ -25,11 +25,11 @@ impl SensorT for FakeSensor {
         3
     }
 
-    fn axis_unit(&self) -> u32 {
+    fn unit(&self) -> u8 {
         // The sensor type is "Meters per second squared", since this is the
         // only, together with "Radians per second", what Google Linux IIO
         // supports (accelerometers and gyroscopes only).
-        SENSOR_UNIT_METERS_PER_SECOND_SQUARED
+        scmi::SENSOR_UNIT_METERS_PER_SECOND_SQUARED
     }
 
     fn axis_name_prefix(&self) -> String {
diff --git a/crates/scmi/src/scmi.rs b/crates/scmi/src/scmi.rs
index 616e4cd..82185b6 100644
--- a/crates/scmi/src/scmi.rs
+++ b/crates/scmi/src/scmi.rs
@@ -216,7 +216,8 @@ pub const SENSOR_CONFIG_GET: MessageId = 0x9;
 pub const SENSOR_CONFIG_SET: MessageId = 0xA;
 pub const SENSOR_CONTINUOUS_UPDATE_NOTIFY: MessageId = 0xB;
 
-pub const SENSOR_UNIT_METERS_PER_SECOND_SQUARED: u32 = 89;
+pub const SENSOR_UNIT_UNSPECIFIED: u8 = 1;
+pub const SENSOR_UNIT_METERS_PER_SECOND_SQUARED: u8 = 89;
 
 enum ParameterType {
     _SignedInt32,
@@ -309,7 +310,12 @@ impl HandlerMap {
             BASE_DISCOVER_VENDOR,
             "base/discover_vendor",
             vec![],
-            |_, _| -> Response { Response::from(MessageValue::String("rust-vmm".to_string(), 16)) },
+            |_, _| -> Response {
+                Response::from(MessageValue::String(
+                    "rust-vmm".to_string(),
+                    MAX_SIMPLE_STRING_LENGTH,
+                ))
+            },
         );
         self.bind(
             BASE_PROTOCOL_ID,
@@ -1144,7 +1150,7 @@ mod tests {
             let mut description = vec![
                 MessageValue::Unsigned(i),
                 MessageValue::Unsigned(0),
-                MessageValue::Unsigned(SENSOR_UNIT_METERS_PER_SECOND_SQUARED),
+                MessageValue::Unsigned(u32::from(SENSOR_UNIT_METERS_PER_SECOND_SQUARED)),
                 MessageValue::String(name, MAX_SIMPLE_STRING_LENGTH),
             ];
             result.append(&mut description);