[  +0.032492] ieee80211 phy1: rt2x00usb_vendor_request: Error - Vendor Request 0x06 failed for offset 0x0404 with error -71
[  +1.222060] ieee80211 phy1: rt2800_wait_csr_ready: Error - Unstable hardware
[  +0.000010] ieee80211 phy1: rt2800usb_set_device_state: Error - Device failed to enter state 4 (-5)

4.5.3 Shared Memory between MCU and host (offset:0x7010~0x701F)
This register is used as the mailbox between the MCU and host driver. It’s valid for RT2860 and RT2980 only.

--- a/drivers/net/wireless/ralink/rt2x00/rt2800lib.c.orig
+++ b/drivers/net/wireless/ralink/rt2x00/rt2800lib.c
@@ -499,7 +499,8 @@ void rt2800_mcu_request(struct rt2x00_de
     /*
      * SOC devices don't support MCU requests.
      */
-    if (rt2x00_is_soc(rt2x00dev))
+    if (rt2x00_is_soc(rt2x00dev) ||
+        !rt2x00_rt(rt2x00dev, RT2860))
         return;
 
     mutex_lock(&rt2x00dev->csr_mutex);