Sony Ericsson txt - Full phone specifications - GSMArena.com
There is no official “Flash File Z” from Sony Ericsson. The term is user-generated shorthand from firmware sharing forums. Sony Ericsson Ck13i Flash File Z
For most users, is the safest free option. It reads .Z archive structures directly if extracted to the proper folder. Sony Ericsson txt - Full phone specifications - GSMArena