Hello all, trying to replace a TP277-6" 6AV6 643-0AA01-1AX0 with a like in kind replacement. I have the simatic MMC 6AV6671-1CB00-0AX2, and I was able to backup the original HMI to this card.
After this, I'm able to restore to the replacement HMI using the Backup/Restore utility. I have two spare HMI's, and both are giving me different issues:

HMI Replacement #1 -- works well for a few hours to a day, then starts to bootloader cycle over and over again. I'm able to do a factory reset with the associated USB to DP siemens cable with Prosave, and restore the HMI again. It will then repeat the process of working well for a few hours, then starting the bootloader cycle. (I assume this issue is maybe related to licensing, but I'm fairly new to Siemens. Do I need to follow:  Operating Instructions, 09/2007, 6AV6691-1DH01-0AB0 section 7.9 Transferring license keys to get this unit to operate properly?)

HMI Replacement #2 -- I'm able to do the Backup/Restore utility, but it won't communicate with the PLC. It doesn't error out as connection not established, but it will error saying it can't write to the specified tag when you try to utilize the HMI.

I'd love to replace and upgrade these components someday, but Siemens support in Northern Minnesota is few and far between. Any help and guidance here is greatly appreciated to help me get this HMI panel replaced. (Backlight is nearly dead on old one.)

S7300 - WINCC Flexible 2005