diff --git a/platforms/common/Serial.cpp b/platforms/common/Serial.cpp
index 9c957fde37..ca338eb190 100644
--- a/platforms/common/Serial.cpp
+++ b/platforms/common/Serial.cpp
@@ -74,9 +74,9 @@ ssize_t Serial::read(uint8_t *buffer, size_t buffer_size)
 	return _impl.read(buffer, buffer_size);
 }
 
-ssize_t Serial::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_us)
+ssize_t Serial::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_ms)
 {
-	return _impl.readAtLeast(buffer, buffer_size, character_count, timeout_us);
+	return _impl.readAtLeast(buffer, buffer_size, character_count, timeout_ms);
 }
 
 ssize_t Serial::write(const void *buffer, size_t buffer_size)
diff --git a/platforms/common/include/px4_platform_common/Serial.hpp b/platforms/common/include/px4_platform_common/Serial.hpp
index 8b2f5e8f1a..fb45b52385 100644
--- a/platforms/common/include/px4_platform_common/Serial.hpp
+++ b/platforms/common/include/px4_platform_common/Serial.hpp
@@ -62,7 +62,7 @@ public:
 	bool close();
 
 	ssize_t read(uint8_t *buffer, size_t buffer_size);
-	ssize_t readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count = 1, uint32_t timeout_us = 0);
+	ssize_t readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count = 1, uint32_t timeout_ms = 0);
 
 	ssize_t write(const void *buffer, size_t buffer_size);
 
diff --git a/platforms/nuttx/src/px4/common/SerialImpl.cpp b/platforms/nuttx/src/px4/common/SerialImpl.cpp
index 19533659d0..7fc5ea7520 100644
--- a/platforms/nuttx/src/px4/common/SerialImpl.cpp
+++ b/platforms/nuttx/src/px4/common/SerialImpl.cpp
@@ -251,7 +251,7 @@ ssize_t SerialImpl::read(uint8_t *buffer, size_t buffer_size)
 	return ret;
 }
 
-ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_us)
+ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_ms)
 {
 	if (!_open) {
 		PX4_ERR("Cannot readAtLeast from serial device until it has been opened");
@@ -264,6 +264,7 @@ ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t char
 	}
 
 	const hrt_abstime start_time_us = hrt_absolute_time();
+	hrt_abstime timeout_us = timeout_ms * 1000;
 	int total_bytes_read = 0;
 
 	while ((total_bytes_read < (int) character_count) && (hrt_elapsed_time(&start_time_us) < timeout_us)) {
diff --git a/platforms/posix/src/px4/common/SerialImpl.cpp b/platforms/posix/src/px4/common/SerialImpl.cpp
index f92e1e308f..822ed4255e 100644
--- a/platforms/posix/src/px4/common/SerialImpl.cpp
+++ b/platforms/posix/src/px4/common/SerialImpl.cpp
@@ -244,7 +244,7 @@ ssize_t SerialImpl::read(uint8_t *buffer, size_t buffer_size)
 	return ret;
 }
 
-ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_us)
+ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_ms)
 {
 	if (!_open) {
 		PX4_ERR("Cannot readAtLeast from serial device until it has been opened");
@@ -257,6 +257,7 @@ ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t char
 	}
 
 	const hrt_abstime start_time_us = hrt_absolute_time();
+	hrt_abstime timeout_us = timeout_ms * 1000;
 	int total_bytes_read = 0;
 
 	while ((total_bytes_read < (int) character_count) && (hrt_elapsed_time(&start_time_us) < timeout_us)) {
diff --git a/platforms/qurt/src/px4/SerialImpl.cpp b/platforms/qurt/src/px4/SerialImpl.cpp
index 294cf34dab..73f8ce8cc4 100644
--- a/platforms/qurt/src/px4/SerialImpl.cpp
+++ b/platforms/qurt/src/px4/SerialImpl.cpp
@@ -173,7 +173,7 @@ ssize_t SerialImpl::read(uint8_t *buffer, size_t buffer_size)
 	return ret_read;
 }
 
-ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_us)
+ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t character_count, uint32_t timeout_ms)
 {
 	if (!_open) {
 		PX4_ERR("Cannot readAtLeast from serial device until it has been opened");
@@ -186,6 +186,7 @@ ssize_t SerialImpl::readAtLeast(uint8_t *buffer, size_t buffer_size, size_t char
 	}
 
 	const hrt_abstime start_time_us = hrt_absolute_time();
+	hrt_abstime timeout_us = timeout_ms * 1000;
 	int total_bytes_read = 0;
 
 	while (total_bytes_read < (int) character_count) {