S54 Instrument panel error with 999999 mileage reading.

[BimmerMCoupe]

Hi all,
I am looking to buy a S54 Z3M coupe and this car has couple problems.
Battery was dead and the seller tried to jump the battery and it somehow messed up the instrument panel and mileage shows 999999 miles now. Also the original dash audio was messed with and doesn't work. The seller thinks the dash audio wasn't installed properly when the previous owner took the after market audio and put back the original one. But the instrument panel was fine until battery went out with radio not working according to the seller.

Can you somehow mess up instrument panel by tinkering with dash audio?

I think the seller tried to short the battery and other home remedies to fix the 999999 error but no luck.

Will replacing and reprogramming the instrument panel fix this 999999 error at the BMW dealer? I have googled around for few days and some folks had luck fixing the problem with just shorting out the battery or simply changing the battery, but there are also few people that changed out instrument panel and couldn't fix the error.
Could someone point me to a source or things to try to fix the problem? I also found few people on eBay claiming they can reprogram/repair the instrument panel but I am not sure about their service.
Please help~

[BimmerBreaker]

Never seen that issue in my many years of being here - and that is not what those ebay sellers fix regarding the gauge clusters

Idk man. Id just run far from that car or get it for a song. It probably needs a new cluster which isnt easy to find

[scenturion]

Could be a number of things -
I know the car you're talking about. Lot of red flags.
The 999999 problem could be a huge number of things: bad cluster, some other bad module, CAN bus issue. There's a lot of diagnostics that would have to go into it even to know what needs replacing.
Considering the stereo wiring was hastily installed and removed in the car, my guess is that there's a systematic electrical system issue that has killed one or more of the modules in the system.