Replicant

also i can flash a recovery image to it using download mode and heimidall

Good. If this wouldn't be possible just buy a 'jig dongle' (for example: http://www.amazon.com/Eopzol-Dongle-Unbricked-Samsung-Galaxy/dp/B00WMDRXM6).

but i cant for some reason boot to the recovery image afterwards

What is, if you flash an alternative recovery for testing reasons? For example the one from here: https://wiki.cyanogenmod.org/w/Install_CM_for_n7100
If you could access this recovery, you could just flash the current Replicant 4.2 0004 image from inside of this, (which replaces you recovery with the Replicant one, again).

is there any likely cause of this?

I don't know, sorry; (probably a hardware / memory failure?). I never had this behavior on my Galaxy S2 before.

i successfully managed to install a different recovery image and it booted

when it booted it was unable to mount anything and measured the internal SD cards size as 0MB

so it seemed like the internal SD card has failed

is it possible to install Replicant on a externel SD card?

when it booted it was unable to mount anything and measured the internal SD cards size as 0MB

Probably this is just the same problem as here: http://redmine.replicant.us/boards/9/topics/11319
when your internal storage was encrypted, before?

so it seemed like the internal SD card has failed

You could try to format it with TWRP (recovery) again. For that you don't have to mount the storage.

is it possible to install Replicant on a externel SD card?

It's possible to install Replicant >from< an externel SD card. But I don't know if there is a good way to switch/redirect sdcard0/emmc -> sdcard1/extSdCard that way, that you successfully bring the whole OS bootable on it. I personally don't believe this is a simple trick. But you could ask that kind of questions perfectly on the XDA Developers forum, if you like.

the card was not encrypted
I have tried formatting the SD card from the TWRP recovery and it always gives errors about how it can mount it

the weird thing is even when i have a external SD card in th device it still fails to mount and to format it

i will try a different recovery image to see if it makes a diffrence

i tried clockworkmod and it successfully booted this time
but the same thing happend

i could not mount or format any of the storage devices even the external SD card

i could successfully send a Replicant package via a sideload to the device but it gave me a error (status 7)

it looks like it may be something more than just the internal SD card not working as the external SD card also failed to mount

do you have any ideas or am i best asking on XDA forums now?

also one more thing to note just incase in means something

the settings and back button now do not light up and they used to even in recovery

do you have any ideas or am i best asking on XDA forums now?

I personally (remotely) have no idea what could be the reason. For more suggestions, I would recommend to ask (parallel) on other sources, if you like.

the settings and back button now do not light up and they used to even in recovery

I switched to recovery now to test that on my i9100. For some seconds my button lights were not glowing (on using them), too.
But after 4-5 seconds inside the recovery, (and several tabs on the left menu-button), they began to glow as expected.

PS: I've found something to your internal <> external storage swapping: http://smartphones.wonderhowto.com/how-to/switch-internal-and-external-memory-samsung-galaxy-s3-and-note-2-0141381/ (but I know this doesn't help you now).

PPS: I probably found a video of your problem (but the possible solution seems to be a bit tricky): https://www.youtube.com/watch?v=dHPoWDQJdZg

PPPS: The video called the issue 'note 2 only logo', so I feed the search engine of my choice with it and got a lot of results, for example: http://thedroidguy.com/2015/06/how-to-fix-stuck-in-boot-logo-issues-on-galaxy-note-2-part-1-107484

Hope this helps a bit.

Thanks a lot for you help i will look at those websites tomorrow