Thanks for the information; got finally sailfishx installed:

Started on sunday, 15:30 ... 00:20 (monday morning got andoid downgraded)

Continued on monday, 20:00 -- 23:20 sailfishx booted the first time.

Quite a few obstacles and trial & errors...

Last thing was that fastboot just did not work after that 'spanish' image flashing (well, how to know what 'wipe' options to tick on that gui...) -- the led always went green when pressing volumeup when connecting usb.

Working 'workaround' was entering 'adb reboot bootloader' when android running (and that MTP usb mode) to get blue led...