diff --git a/src/core/devices/nm-device.c b/src/core/devices/nm-device.c
index e926885931..778b748df6 100644
--- a/src/core/devices/nm-device.c
+++ b/src/core/devices/nm-device.c
@@ -3145,12 +3145,9 @@ _set_ip_ifindex(NMDevice *self, int ifindex, const char *ifname)
 
         nm_platform_process_events_ensure_link(platform, priv->ip_ifindex, priv->ip_iface);
 
-        if (nm_platform_kernel_support_get(
-                NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE)) {
-            nm_platform_link_set_inet6_addr_gen_mode(platform,
-                                                     priv->ip_ifindex,
-                                                     NM_IN6_ADDR_GEN_MODE_NONE);
-        }
+        nm_platform_link_set_inet6_addr_gen_mode(platform,
+                                                 priv->ip_ifindex,
+                                                 NM_IN6_ADDR_GEN_MODE_NONE);
 
         if (!nm_platform_link_is_up(platform, priv->ip_ifindex))
             nm_platform_link_change_flags(platform, priv->ip_ifindex, IFF_UP, TRUE);
@@ -6095,10 +6092,8 @@ realize_start_setup(NMDevice *            self,
         if (priv->firmware_version)
             _notify(self, PROP_FIRMWARE_VERSION);
 
-        if (nm_platform_kernel_support_get(
-                NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE))
-            priv->ipv6ll_handle = (nm_platform_link_get_inet6_addr_gen_mode(platform, priv->ifindex)
-                                   == NM_IN6_ADDR_GEN_MODE_NONE);
+        priv->ipv6ll_handle = (nm_platform_link_get_inet6_addr_gen_mode(platform, priv->ifindex)
+                               == NM_IN6_ADDR_GEN_MODE_NONE);
 
         if (nm_platform_link_supports_sriov(platform, priv->ifindex))
             capabilities |= NM_DEVICE_CAP_SRIOV;
@@ -11203,9 +11198,6 @@ set_nm_ipv6ll(NMDevice *self, gboolean enable)
     NMDevicePrivate *priv    = NM_DEVICE_GET_PRIVATE(self);
     int              ifindex = nm_device_get_ip_ifindex(self);
 
-    if (!nm_platform_kernel_support_get(NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE))
-        return;
-
     priv->ipv6ll_handle = enable;
     if (ifindex > 0) {
         int r;
diff --git a/src/core/platform/tests/test-link.c b/src/core/platform/tests/test-link.c
index 500a008751..394274daf3 100644
--- a/src/core/platform/tests/test-link.c
+++ b/src/core/platform/tests/test-link.c
@@ -602,7 +602,7 @@ test_bridge_addr(void)
     g_assert(plink);
     g_assert(!nm_platform_link_get_permanent_address(NM_PLATFORM_GET, plink, &hw_perm_addr));
 
-    if (nm_platform_kernel_support_get(NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE)) {
+    if (nmtstp_is_root_test()) {
         g_assert_cmpint(nm_platform_link_get_inet6_addr_gen_mode(NM_PLATFORM_GET, link.ifindex),
                         ==,
                         NM_IN6_ADDR_GEN_MODE_EUI64);
diff --git a/src/libnm-platform/nm-linux-platform.c b/src/libnm-platform/nm-linux-platform.c
index 30c0678c40..f22e2fdb5e 100644
--- a/src/libnm-platform/nm-linux-platform.c
+++ b/src/libnm-platform/nm-linux-platform.c
@@ -1279,16 +1279,6 @@ _parse_af_inet6(NMPlatform *        platform,
         token_valid = TRUE;
     }
 
-    /* Hack to detect support addrgenmode of the kernel. We only parse
-     * netlink messages that we receive from kernel, hence this check
-     * is valid. */
-    if (!_nm_platform_kernel_support_detected(
-            NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE)) {
-        /* IFLA_INET6_ADDR_GEN_MODE was added in kernel 3.17, dated 5 October, 2014. */
-        _nm_platform_kernel_support_init(NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE,
-                                         tb[IFLA_INET6_ADDR_GEN_MODE] ? 1 : -1);
-    }
-
     if (tb[IFLA_INET6_ADDR_GEN_MODE]) {
         i6_addr_gen_mode_inv = _nm_platform_uint8_inv(nla_get_u8(tb[IFLA_INET6_ADDR_GEN_MODE]));
         if (i6_addr_gen_mode_inv == 0) {
@@ -7517,11 +7507,6 @@ link_set_inet6_addr_gen_mode(NMPlatform *platform, int ifindex, guint8 mode)
           ifindex,
           nm_platform_link_inet6_addrgenmode2str(mode, sbuf, sizeof(sbuf)));
 
-    if (!nm_platform_kernel_support_get(NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE)) {
-        _LOGD("link: change %d: user-ipv6ll: not supported", ifindex);
-        return -NME_PL_OPNOTSUPP;
-    }
-
     nlmsg = _nl_msg_new_link(RTM_NEWLINK, 0, ifindex, NULL);
     if (!nlmsg || !_nl_msg_new_link_set_afspec(nlmsg, mode, NULL))
         g_return_val_if_reached(-NME_BUG);
diff --git a/src/libnm-platform/nm-platform.c b/src/libnm-platform/nm-platform.c
index 7c84c4dad5..531052bdb3 100644
--- a/src/libnm-platform/nm-platform.c
+++ b/src/libnm-platform/nm-platform.c
@@ -306,12 +306,6 @@ static const struct {
             .name                 = "EXTENDED_IFA_FLAGS",
             .desc                 = "IPv6 temporary addresses support",
         },
-    [NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE] =
-        {
-            .compile_time_default = TRUE,
-            .name                 = "IFLA_INET6_ADDR_GEN_MODE",
-            .desc                 = "IFLA_INET6_ADDR_GEN_MODE support",
-        },
     [NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF] =
         {
             .compile_time_default = (RTA_MAX >= 20 /* RTA_PREF */),
diff --git a/src/libnm-platform/nm-platform.h b/src/libnm-platform/nm-platform.h
index 8f50e4ef3e..ee914d00ce 100644
--- a/src/libnm-platform/nm-platform.h
+++ b/src/libnm-platform/nm-platform.h
@@ -1016,7 +1016,6 @@ typedef void (*NMPlatformAsyncCallback)(GError *error, gpointer user_data);
 
 typedef enum {
     NM_PLATFORM_KERNEL_SUPPORT_TYPE_EXTENDED_IFA_FLAGS,
-    NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE,
     NM_PLATFORM_KERNEL_SUPPORT_TYPE_RTA_PREF,
     NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_L3MDEV,
     NM_PLATFORM_KERNEL_SUPPORT_TYPE_FRA_UID_RANGE,
@@ -1403,8 +1402,6 @@ _nm_platform_link_get_inet6_addr_gen_mode(const NMPlatformLink *pllink)
 {
     if (!pllink)
         return -ENODEV;
-    if (!nm_platform_kernel_support_get(NM_PLATFORM_KERNEL_SUPPORT_TYPE_IFLA_INET6_ADDR_GEN_MODE))
-        return -EOPNOTSUPP;
     return _nm_platform_uint8_inv(pllink->inet6_addr_gen_mode_inv);
 }