When I associated R750 to SZ 5.2, it shows me below.
AP Image Signing: AP [RuckusAP@xx:xx:xx:xx:xx:xx] with firmware version [112.1.0.0.2146] is USI. USI to FSI upgrade is not allowed due to difference in Image formats.
Yes it is. the AP should get upgraded with this alarm in our experience. If your R750 cannot associate, we can provide you with the AP image SZ5.2. In order to follow up, it is recommended to have a case log in our ticket system.