I bought the dongle along with the inverter. Directions specify there will be updates when the dongle is first used. The Phoenix inverters are described by the tech person at Northern Arizona as being pretty straightforward. There were never any error codes with our inverter. There is a way to send Victron via email some kind of performance report but users are not able to read it. I sent a that report to Northern Arizona but got nothing from them as to its usefulness. What I got from tech was Victron units might rarely be dead on arrival but for it to fail as ours did is unusual.
Victron wants you to go through the vendor you purchased for service/warranty. The tech person walked me through several tests over the phone where I used a multimeter. He also had me confirm parameter settings were default and firmware was up to date from the dongle connection. Then he submitted a warranty claim with Victron. Less than a week later I got a call from another person from Northern Arizona informing me that Victron will send a new unit. I did not argue about paying the shipping for the new inverter, choosing the least expensive option. Northern Arizona kicked in the additional amount for 2 day shipping, apparently. The new one functions just fine so far.
I was hoping to tap into the great minds here on diysolarforum to see if the defective inverter might be brought to life, but got a little snoot directed towards me (could have been partly how I explained the tribulations with the bad batteries but probably the simple, rather crude methods I used without BMS and such raised some ire) so put that on pause.
Wondering where you got your inverter and how long you have had it.