I fully understand your concern, before solving this issue for you, please check and make sure that the firmware upgrade is only for the EU countries.
If you did using in the EU countries and upgrade fails, don't worry, you can escalate to the manual support. let's help you resolve this step by step.
Firstly we'll walk you through the operation steps together.
If you’d prefer step-by-step guidance or the upgrade still fails, we'll help you to find the corresponding technical support.
If it still fails and it's defined as the product issue by technical support, we may consider to provide you with a free return and we’ll send you a brand-new replacement.