To be fair I do not keep up to date on the map stuff as my maps work just fine for me and if they dont then i use the phone.
https://forums.seatcupra.net/index.php?threads/navigation-system-updates.388586/ is where I always go to for info and if i have read it correctly MIB1 is new map sd and pay the stealers to enable it on your car.
There are some Android headunits that will support the car menus and allow you to run Waze and or Google Maps but for me they are no good as they dont support Traffic Sign Recognition and Seat Sound but I keep hunting.
@Tell did say way back in the day some people managed to update the MIB1 but there were no clear instructions that others could follow so afraid after all the chat the answer is not that i am aware - but i dont pay much attention to it.
We know what we need to do with mib2 sd the overall.nds trick attributed to Exciter, mib2 plus (high) unit get it turned into a retrofit then the world is your oyster. Mib1 SD this is where some people were buying cards back in 2016 and getting it to work, others followed this avenue but couldn't. That's back in 2016 on the thread:
https://forums.seatcupra.net/index.php?threads/navigation-system-updates.388586/page-92
I wondered whether the success was associated with the unit having Mapcare on it, nobody knew but a few people were out of pocket going to ebay sellers, since the card still needed to be activated.
Now somebody of recent had messed up their mib1 card and got somebody to email their files which fixed it, this also happened in the past with someone. Mib2 SD if you delete all contents and loose the overall.nds file you just need to download the version that was on the card from a Vag website for those with Mapcare. The SD card has a CID on it locked to the unit, and the overall.nds file of the original card is also locked to it. Hence the Exciter method works protecting the card from copying but not protecting it from updates. Whilst the Exciter method of updating the maps in mib1 isn't available, re-writing the version that was lost does work the same.
I'm not sure whether the CID is a series CID common to the release or unique to the card. Pretty sure it's unique to the card. You have to swap cards between cars on the same map year to test although any card swapping runs a risk. They are designed if you have Mapcare to be able to do it that way between releases. That's where people on mib2 get into a pickle with the workaround thinking they can buy a spare more up-to-date card and the unit locks to the new card and the old one stops working defeating what they were trying to do (but still do the mib2 workaround with the new card, £80 down ). You can buy a "gold" card for that, about £40 but you need a Mac or Linux and some software. Bog standard PCs dont write CIDs and standard SD card don't have re-writeabls CIDs. Exciter on the thread also created a clone SD card for the hell of it but I reckon if the SD card got corrupted take the financial hit unless you got Linux experience then perhaps create a proper backup. The SD card wont get corrupted through normal use or updates so taking a backup with CID isn't really required.
From all of this I don't think any mib1 buy a card off eBay and DIY generally works. Instances maybe where they bought the same release or in the early days the unit had Mapcare. On the thread we don't really know any mib1 workarounds that worked for everyone. Situation with Mib2 is much clearer how it all works.