Can anyone answer my question in the above post?

I tried replacing the Chinese ROM with the Taiwanese ROM not realising that as I had allowed the tablet to install an update from 5.0.2 to 5.1.1 the install wouldn't work. I was using the flash image option in fast boot.  Apparently the device needs to be rooted and ADB used instead. For some reason it is not possible to root the device with the Nokia version of 5.1.1 installed.

I was able to flash the recovery and boot images but the system one fails with the message "Invalid sparse file format at header magi"

Foolishly I didn't create a backup. I cannot find a copy of the original Chinese ROM.

I'm stuck in fastboot mode, in other words I cannot use ADB as USB debugging is turned off.

I'm hopeful that if I can get ADB to work I may be able to root the device and may have success installing the Taiwanese ROM.

One route I want to try is to install another ROM that has been built for the Intel Atom chip. I don't expect all the functionality to work but at hope I can switch on USB debugging and then hopefully root the device to be able to use ADB.

Am I likely to have some success installing an Intel Atom ROM from another device.

Pretty much no you may get away with an 3rd party ROM like an CM ROM or the like if someones made one but you may run into problems like the camera or WiFi not working 

Thanks for the reply.

Looks like I need to find a copy of the Chinese ROM.

Is there any harm in trying another ROM? What's the worst that can happen? I don't need everything to work. 

If you haven't already, head over to XDA. It's a more specialist forum. 

They even seem to have a category for Nokia N1 threads. What a _very_ quick look, in one thread it looked like someone tried what you're thinking (flashing firmware for an alternative device with the same processor) and made a brick even brickier.

I've been looking and posting on XDA. I missed the post you refer too. 

So far I've had no response to my plea for help on XDA, hence my post here on Geekzone.

Thanks for your help.