How to unlock W810i ?

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How I can create these files w810_p3k_dcu.49R.ssw & 2. rest_W810_R4EA031.bin?

Click [Add] button on SETool 2 Lite select the file according to your phone model, in my case, ‘w550_r2e_dcu.49r.ssw’ (for W550i CID49) .
I've read on other threats that I have to apply to my phone only firmware with the same erom cid as is on the phone,in my case cid 50.
If I apply w810_p3k_dcu.49R.ssw which has cid 49, the phone won't be damaged?

Click [Add] button on SETool 2 Lite select the file according to your phone model, in my case, ‘w550_r2e_dcu.49r.ssw’ (for W550i CID49) .
I've read on other threats that I have to apply to my phone only firmware with the same erom cid as is on the phone,in my case cid 50.

it flashes 5 blocks which make the w550i phone to read and write by Farmanager plugins "sefp",so I'd told you that you need ‘w810_p3k_dcu.49r.ssw’ file.
using "rest" files restore the main firmware.if you don't use "rest" files you can't switch on your phone.
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If I apply w810_p3k_dcu.49R.ssw which has cid 49, the phone won't be damaged?

you're right.