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I recently upgraded my phone from a Galaxy S5 Mini to a Galaxy S7, from a 3rd party supplier, and since doing so I have virtually no mobile phone signal at home. With my S5 Mini I had a reasonable signal. After a couple of months of trying to sort out with Vodafone and Samsung, I was advised today at a Samsung Repair Centre that the phone was made in the USA. I have been trying to establish why I am not able to set up wi-fi calling, which I was hoping would sort my problem out for me, and having googled it would appear that the US firmware on the phone is preventing this. There appears to be some solutions offered on the internet, and that the US firmware can be replaced with a UK firmware. Can anybody confirm this to be the case and if so has anybody successfully installed the UK firmware that would then enable wi-fi calling to be accessed and used?
I imported my N20 Ultra from Hong Kong because it uses broader bands and frequencies than that of it's USA counterpart @Bonny
You can change the CsC and install a Custom Rom but you would need to be careful as Samsung UK won't typically help with an imported phone if it goes wrong.
I'd suggest to check on the xdadevelopers.com site for support if your going ahead with trying this.
Disclaimer. Please be aware that if it does go wrong you could end up with stability issues or a non working phone in the worst case scenario.
I wish you all the best with this.
Current Phone > Samsung Note 20 Ultra 5G - SM9860 Snapdragon.
Samsung One Ui 2.5 / Android 10.