Ok finally fixed it and for people having similar issues flashing their n9 this might come in handy.

It appears that not only does the variant number have to be higher or equal, also the following numbers have to be higher. For example I had

DFL61_HARMATTAN_40.2012.21-3.350.3

installed. It appears that this actual firmware does not really exist for my product code. It did for a previous PR but got changed to variant 430, but as I updated via OTA the firmware variant never got changed to the correct 430. It kept the 350.3 part and replaced the 40.2012.21-3 to resemble the PR1.3.

Having to flash my phone now there is only this 430 variant available for my product code which is precisely:

DFL61_HARMATTAN_40.2012.21-3.430.01.1

One would think coming from a 350, flashing to 430 wouldn't be a problem because the variant number is higher. But no, it doesn't work because of big a** version numbering inconsistency fail. As you can see it's actually variant 350.3 vs 430.01(.1) and apparently the numbers following the 350 and 430 variant codes ALSO WILL BE COMPARED.

So I was looking around for a firmware that has both the variant number and what follows after it at equal or higher numbers and I found this N9 Rm-696 Optimus Pt V1-black - 16g firmware named:

DFL61_HARMATTAN_40.2012.21-3.398.3

And voilá that damned thing works again.