Feasibility of flashing a ROM (meant for original device) on a re-branded device I have a re-branded smartphone with Android 5.0. The thing is I want to install a custom ROM to remove all the bloatware and get more control. But, as it is re-branded   and not that popular there are not any custom ROMs available for it.

What I'm thinking is that since its hardware is not that old and there are many popular smartphones with exactly the same specifications, is it possible to install a custom ROM that was not built for my smartphone but was built for one which has exactly similar specifications?

Note: I can post the specifications, if required.
If all the specifications match, including chip level and GPU Mali blobs, it sounds a reasonable try, though I never owned a re-branded device.

After taking complete backup including EFS and double checking, I would suggest first flash the kernel from the proposed ROM to replace the existing kernel. If it boots properly and basic functionality of phone is fine, then you can flash the complete ROM. This way you are ruling out kernel compatibility issues.