[TG] [TG11] E120 Reinstall 4.30

[JoeZInc]

Installed an RD424 HD onto an existing dual E120 system using the new cable and latest software (5.69) upgrade.
All went well and the with Radar operating via both E120's responding to input from the MFD's as desired.
After about an hour I rxd a call from the owner saying he could not get either MFD to display radar.
Upon my return:
The radar icon remained greyed out. Once the warm up message indicated the unit was ready to transmit , it would not transmit
Voltage both under load and at the power connector appeared nominal. ~12.8 vdc.
Swapped ethernet ports on the HS switch no change there
Operation was fine with no issues with with either MFD during upgrade.
Returned TWO radars after figuring we had a bad RD424 resulting from a brief chat with support. We agreed later that 2 bad RD's were unlikely
THEN
Started to lose fix ~20 to 25 times per day trip.
My guy wants to go fishing.
I've successfully downgraded other (NON RAYMARINE) systems with success.
SO.....
Nextstep:
Contacted 1st level who opened case 200508-000043
2nd level recommended downgrade to 4.30
I cannot find a copy to download.
I do see issues raised about downgrades

Which is it ?
What are my next steps?