Valvetronic Errors After BMW Software Update

[BimmerBimmerChickenDinner]

Hi there, has anyone else experienced anything like this? I have a BMW M4 F82 that had a sidelight/drl issue and as part of some of the attempted fixes a full BMW software update was carried out which happened to remove my tune/remap but not only that - the next time I started up my car after having it jacked up on axle stands at the front for about 3 weeks whilst working on it it seems to have suddenly developed a valvetronic error? It had the classical woodpecker noise when unlocking and locking the vehicle aka waking up the DME I believe, weirdly enough I found that my battery cables were a bit loose and after tightening the connections the issue/clicking seemed to go away completely, I plugged in ista and it said the valvetronic issues were then non existent, plugged the laptop into the car again the day after to wipe the codes and they then came back and were marked as existing? Could this potentially be battery related? The car has been laying up for quite some time and so it's possible the battery is on it's way out... Or do I most likely need to replace the servomotor and possibly the eccentric shaft? Should I attempt a valvetronic calibration in ISTA? The car isn't under warranty and so I will most likely be doing the work myself or going to a local Indy shop, any help or advice would be much appreciated, thanks!

[BimmerBimmerChickenDinner]

I will update later with the exact codes, it started with a single valvetronic code which was 135808 - Valvetronic servomotor, position sensors: Malfunction' but now there's a few more which I will post later today after I finish work...