Unfortunately doesn't seem to be a solution, so my recommendation is not to upgrade the firmware of your DELL monitor if it is out of warranty. Mine was working perfectly and now is broken and DELL doesn't provide any kind of support for this other than "replace your ($900) monitor".
Hi, I tried to upgrade my U3419W monitor to the latest firmware M3B114 from M3B107 and the updating process failed with "Flash erase error". Now the USB-C port  doesn't work anymore. I have called to DELL support Spain (paid phone number), and after 30 minutes answering questions to a bot, a support person told me that they don't provide any kind of support to monitors out of warranty. What can I do?
U3419W, firmware upgrade M3B114 error, USB-C port no working