Two of my designs are part of the same TT02 chip that houses the 'secret file'. These are not 'programs' but rather hardware logic designs that were etched into silicon using a 130nm manufacturing process (this is what Intel and AMD were using in the early 2000's to make CPUs). Each project contributor was able to build their silicon projects using free open source tools. For less than USD$200 each contributor received a design slot on the chip, and a demo board with the custom chip. The design submission window closed in Nov 2022, and the board with the custom chip was delivered in Feb 2024.

(When I saw the 'secret file' submission in Nov 2022, I decoded it from the source code to make sure the file wasn't anything nefarious. When I saw it was a rick-roll I died laughing. Well played.).

My guess is that they (Best Buy) cross referenced the name they read from my credit card to one of the bulk mail lists they purchased for marketing purposes. The letter was addressed to me 'or current resident' and inside was information about how my player with this new firmware update could download Netflix movies. The update CD itself was for my specific model (BD-P2550).

The other possibility is that they cross-referenced my in store purchase via the card number to a previous on-line purchase from their web store (which would have included a shipping address). In either case, the mag stripe of my card (in an otherwise anonymous transaction) was used to make the connection, and four months later a package with a firmware update arrives at my house.

Yes, it was Best Buy who shipped the update DVD, not Samsung. But still... an update service who ships updates to you based on your mag stripe. Scary.