As the title says, I am wondering if there are any flashcart specific rules. I randomly generated a game to learn how to speedrun for the new year, and this is the game that came up. I am just wondering if there are any specific rules on flashcarts (Everdrive specifically) until I can find an original cart locally.

Welcome to the gaiden

There's currently no flashcart specific rules, other than the obvious things you can't do on console(in other words don't use savestates in your submitted run).

Other than that, the only exception is if a glitch/bug occurs that lets you beat the game faster. A handful of runners have at times gotten the game to skip parts of the game(an example is the jaquio skip, where it loads the 3rd final bossfight in the 2nd's room).

^ these are very rare; we don't know how they work nor have confirmation that they're possible on the original cart. If you were to finish a PB with that, it would likely fall under the "That's highly impressive, but not allowed" category. Again, very rare and generally not a concern. :)