I'm at a very early stage of ECU tuning, the initial thought was that I'd like to try reducing the engine's fuel consumption, even for just a small amount to have a sort-of "proof of concept" that this might work and give some results ... the car in question is a Skoda Superb 3.6 FSI '08, and its ECU is a Bosch MED 9.1.1 ... I've obtained a working MPPS v16 clone, managed to get the map dump without problems (it took ~20 minutes, a 2 MB file), and that on the battery voltage of 11.89V ... after that, I've sent (and paid) my original map file to a tuning specialist (they're not that close to me to have this done in person), and they returned the ECO map back ... I've checked the original and ECO map with WinOLS, and I see that they did some changes (not going into what they did at this time, some values are raised, some are lowered - that's all I ca see and understand at this point).

Now, this is where I'd like an expert opinion, the returned ECO file didn't have an extension (like .bin or whatever), but I can open it with WinOLS and, do the checksum (no errors reported) and export as a .bin file (like the original map). "All" that's left is to put the new map to the car, but I'm hesitant to do that, after I've read various online sources about the prerequisites etc. If I'm right (based on other sources), the car battery voltage (of course, no engine running and can't be connected to the auxiliary power source), must not be lower that 12V or the ECU will be bricked during the write procedure (my battery is obviously somewhat older, but works without issues when the engine needs to be started). The other thing is that the MED9.1.1 and MPSS v16 supposedly don't go together in terms of writing. The tuning company uses KESS v2 so they can't help me with this. As a reference, I've used this topic here: http://nefariousmotorsports.com/forum/index.php?topic=10126.0, where the OP is playing around with the almost similar ECU (don't know if that last .1 in the ECU version makes that big a difference from mine) with the MPPS v16 without issues.

So, what now? Can I proceed with the flash/write, or will I just brick my ECU (if I had a close tuning company for backup solution/ECU restore if worst comes to worst, I'd just go ahead and try). Thanks in advance for any helpful and reassuring input.

What worries me is that the write procedure (comparing to the read procedure), will also (probably) take at least 20 minutes, I don't think the battery will last for that long (a fair question would be why I don't get a  new battery in that case, but since it is an AGM, I would need to invest more than in the MPPS and the modified map file ... and this one works), because when the car is off, the radio will play for 15 minutes at most, before its "battery-save" mode kicks in ...

Wouldn't the external battery charger connected to the car battery (which is still connected to the car) also cause potential issues during the MPPS read/write?

One other thing, regarding the MPPS ecu checksum, this is the last step before actually doing the write - supposedly on this ECU it can't do the checksum (not supported), but it doesn't matter anyways if you check the ECU's checksum beforehand (like in WinOLS), does this sound right?

I did write in my first post that "I'd like to try reducing the engine's fuel consumption, even for just a small amount to have a sort-of "proof of concept" that this might work and give some results", I don't actually expect miracles (not that big of an idiot ... ), but it was done out of curiosity and to maybe start experimenting on my own with the ECU remaps step-by-step on the car and see what I can do with it ... I could've went the other route, expecting to get 40-60 HP out of the ECU remap, and then you would still get the same opening question from me ...

And that's what I appreciate - results (or lack of) are only my concern in this case, I just don't want to do damage to the ECU before actually accomplishing at least something from the stock starting position ... the immobilizer issue doesn't exist on this ECU (I've read on some other places that you can loose the immo info and then be unable to start the car after doing a remap)

MPPS will checksum this file. The rest is wildcard

This one is not an assumption, it checksummed correctly while importing the file following several online tutorials on how to do the checksum within it, no errors reported afterwards ... but I like that the professionals are very professional about this, especially in the noob section ... I guess you all were born with the remap knowledge before entering elementary school, sorry for appearing before the mighty lot of you (maybe what I'm asking is what others wanted to know but were afraid to ask, seeing the feedback) ... I've asked what I want want to know in the beginning, you can ignore the rest of the assumptions or circumstances, I just want to put the ECU file properly to the car's ECU at this point without bricking it, because there is a lot of everything available on the net, but you can never be too sure about who writes and what they write ... will the new map blow my cylinders off afterwards, who knows, maybe ... you'll be the first ones to know ...

And, like pjr wrote, probably money wasted - fair enough, point noted - I never said it probably won't be like that, but I'm the one that likes to try somethings for himself regarding the cars, anything bad in that? I was mostly into car electronics and multimedia until now, this is something new to me for now.

I'd be very curious to see if the fuel consumption can in any way be reduced with the remap (even by a very small margin) ... what pjr wrote, regarding the cold start, the FSI engine takes some 10-15 seconds working on 1200 RPM when cold, before dropping to normal 650-700 RPMs ... if the ECU remap can at least impact this somehow, then why the hell not, it will already be worth the trouble ... if I was that worried about actual fuel economy, I wouldn't obtain a 260 HP car, right? This is more of an exploration of what can be achieved ... was also thinking about throttle pedals and such, this is much cheaper and unobtrusive in a physical sense

This can easily be achieved, I believe you meant lowering the consumption ...