diff --git a/src/nm-initrd-generator/nmi-cmdline-reader.c b/src/nm-initrd-generator/nmi-cmdline-reader.c
index 2afdb8dedd..367962d99d 100644
--- a/src/nm-initrd-generator/nmi-cmdline-reader.c
+++ b/src/nm-initrd-generator/nmi-cmdline-reader.c
@@ -1173,13 +1173,13 @@ reader_parse_rd_znet(Reader *reader, char *argument, gboolean net_ifnames)
 static void
 reader_parse_ethtool(Reader *reader, char *argument)
 {
-    const char *    interface   = NULL;
-    NMConnection *  connection  = NULL;
-    NMSettingWired *s_wired     = NULL;
-    const char *    autoneg_str = NULL;
-    gboolean        autoneg     = FALSE;
-    const char *    speed_str   = NULL;
-    guint           speed       = 0;
+    NMConnection *  connection;
+    NMSettingWired *s_wired;
+    const char *    autoneg_str;
+    const char *    speed_str;
+    const char *    interface;
+    int             autoneg;
+    guint           speed;
 
     interface = get_word(&argument, ':');
     if (!interface) {
@@ -1192,38 +1192,40 @@ reader_parse_ethtool(Reader *reader, char *argument)
         return;
     }
 
-    connection = reader_get_connection(reader, interface, NM_SETTING_WIRED_SETTING_NAME, TRUE);
-    s_wired    = nm_connection_get_setting_wired(connection);
-
     autoneg_str = get_word(&argument, ':');
+    speed_str   = get_word(&argument, ':');
+
+    autoneg = -1;
     if (autoneg_str) {
         autoneg = _nm_utils_ascii_str_to_bool(autoneg_str, -1);
         if (autoneg == -1)
             _LOGW(LOGD_CORE,
                   "Invalid value for rd.ethtool.autoneg, rd.ethtool.autoneg was not set");
-        else
-            g_object_set(s_wired, NM_SETTING_WIRED_AUTO_NEGOTIATE, autoneg, NULL);
     }
-    if (!*argument)
-        return;
 
-    speed_str = get_word(&argument, ':');
+    speed = 0;
     if (speed_str) {
-        speed = _nm_utils_ascii_str_to_int64(speed_str, 10, 0, G_MAXUINT32, -1);
-        if (speed == -1)
+        speed = _nm_utils_ascii_str_to_int64(speed_str, 10, 0, G_MAXUINT32, 0);
+        if (errno)
             _LOGW(LOGD_CORE, "Invalid value for rd.ethtool.speed, rd.ethtool.speed was not set");
-        else
-            g_object_set(s_wired,
-                         NM_SETTING_WIRED_SPEED,
-                         speed,
-                         NM_SETTING_WIRED_DUPLEX,
-                         "full",
-                         NULL);
     }
 
-    if (!*argument)
-        return;
-    else
+    if (autoneg == -1)
+        autoneg = FALSE;
+
+    connection = reader_get_connection(reader, interface, NM_SETTING_WIRED_SETTING_NAME, TRUE);
+    s_wired    = nm_connection_get_setting_wired(connection);
+
+    g_object_set(s_wired,
+                 NM_SETTING_WIRED_AUTO_NEGOTIATE,
+                 (gboolean) autoneg,
+                 NM_SETTING_WIRED_SPEED,
+                 speed,
+                 NM_SETTING_WIRED_DUPLEX,
+                 speed == 0 ? NULL : "full",
+                 NULL);
+
+    if (*argument)
         _LOGW(LOGD_CORE,
               "Invalid extra argument '%s' for rd.ethtool, this value was not set",
               argument);
diff --git a/src/nm-initrd-generator/tests/test-cmdline-reader.c b/src/nm-initrd-generator/tests/test-cmdline-reader.c
index f2ad5470ff..ccdb8ab7be 100644
--- a/src/nm-initrd-generator/tests/test-cmdline-reader.c
+++ b/src/nm-initrd-generator/tests/test-cmdline-reader.c
@@ -2403,10 +2403,10 @@ test_rd_ethtool(void)
     _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:off:0", "rd.ethtool=eth0:off"), FALSE, 0);
     _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:on:0", "rd.ethtool=eth0:on"), TRUE, 0);
     _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:on:0", "rd.ethtool=eth0:off"), FALSE, 0);
-    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:off:100", "rd.ethtool=eth0:on"), TRUE, 100);
-    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:off:100", "rd.ethtool=eth0:off"), FALSE, 100);
-    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:on:100", "rd.ethtool=eth0:on"), TRUE, 100);
-    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:on:100", "rd.ethtool=eth0:off"), FALSE, 100);
+    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:off:100", "rd.ethtool=eth0:on"), TRUE, 0);
+    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:off:100", "rd.ethtool=eth0:off"), FALSE, 0);
+    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:on:100", "rd.ethtool=eth0:on"), TRUE, 0);
+    _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:on:100", "rd.ethtool=eth0:off"), FALSE, 0);
 
     NMTST_EXPECT_NM_WARN("cmdline-reader: Could not find rd.ethtool options to set");
     _ethtool_check_v(NM_MAKE_STRV("rd.ethtool=eth0:off:100", "rd.ethtool=eth0:"), FALSE, 100);