Flashing OpenWrt on Linksys MR8300 - partially bricked

Is the MR8300 conversion to OpenWRT still only via serial ?

I have several issues with the OEM firmware :

  • Wi-Fi drops every once in a while
  • Impossible to have stable Wi-Fi on iPhones 7 and 8 using Zoiper voip soft phone, which keeps de-registering showing "not ready"
  • OEM firmware completely dummed out compared to EA8300

So I just bought a refurbished EA8300, namely because of OPENWRT support, price, very decent flash + ram size, double firmware backup.

Flashed this baby twice to latest OEM firmware, in order to fall back if required. I then proceeded to flash to 19.07.3 and WOW :

  • In the farther rooms, now getting full 3 bar signal on my iPads and iPhones, where I only got 2 bars with my previous routers Archer C60 and the MR8300
  • No more intermittent Wi-Fi drops
  • Most importantly Zoiper works perfectly now with my iPhones

I must say I had previously bought an EA8300 prior to the MR8300 back in 2019, but it didn't fix the C60 signal strength issue and as such I returned it.
I later got my hands on the MR8300 for $100 CAD new, primarily lured by killer price, mesh and the fact the EA's firmware was quite a step up from my C60's. What a deception the dummed MR was compared to the EA, but I decided to keep it considering the killer price and decent upgrade to the C60.

However, as impressed I am with the EA's brain surgery, I am now itching to upgrade my MR8300 to same. However, I would very much prefer to avoid using a scalpel with a serial intervention.

My questions here are as follows :

Has the MR8300 been locked out from GUI upgrade by Linksys the way TP-LINK did to my C60, or this is an issue that will be resolved in a future release of OpenWRT ?

Also, do I just need to be patient and official support is in the works ?

This is my first post here, hopefully I didn't rant too much...

I really like OpenWRT, never felt so much in control before !