Changing roms

[Danielgregory]

Hi,  I am looking to try a different rom on my Xperia 1 II as my mobile service seems to be quite poor. I also do not get 5G/Volte.  I believe I currently have either the CN or HK rom. I intend to try either the Taiwan or SEA rom. I am in Australia.  Is it relatively easy to swap ROMs on this phone? As I am installing an offical rom, do I have to root the phone?  If I have to root the phone, what do I lose in features? I understand rooting/unlocking the phone will stop DRM features from working?  Is it possible to just swap the modem firmware with out rooting/installing another rom?  I have heard installing another rom will not change the modem firmware and therefore will not change the phone service? Is that correct?  Thank you for any help.

[Lord_viridis]

Flashing an official rom via a flash tool won't require rooting, so no drm keys will be affected in any way.

You MUST make sure the model numbers match or you could risk bricking the handset completely.

In regards to modem, if the firmware is a "full package" it will / should overwrite the current modem configuration with the new fw.

There are guides on other sites about flashing as it's not something we generally discuss on here due to the potential damage flashing can do to a handset if done incorrectly.

But once more, make sure model numbers are exactly the same.

[Danielgregory]

Hi,

Thank you for the help.

How can I make sure the rom I download is a full package?

[Lord_viridis]

Most official fw are full packages.

Fw Without modem updates are rare tbh

[Danielgregory]

Thanks for the reply.

If I were to unlock the bootloader, do you know what I would lose? I have heard it can cause the camera quality to be worse and cause issues with the Netflix app? Anything else?

Something to do with DRM?

[Lord_viridis]

You won't need to unlock the bootloader for official roms.

Anything beyond official rom flashing will, and could cause loss of drm keys and other functionality (or at least it did when I last looked into it a few years back)

[Danielgregory]

I'll try another official rom first.

If that does not work then I might go the bootloader path.

But I do not want to lose features either.

Thank you for your help.

I might have more questions later on.

[EMS_MO72]

Hey @Danielgregory 

If you'll go for unlocking the bootloader, this link will be helpful: https://developer.sony.com/open-source/aosp-on-xperia-open-devices/get-started/unlock-bootloader

[Danielgregory]

Hi，thanks for that link.

Any idea how I can check what rom I have on my phone already? HK, SEA etc?

And I was downloading the official SEA rom but it was called customised SEA. What does the customised mean exactly? Not customised by someone?