Okay, so for those of you that would be stuck at any point in the new latias challenge, here I am :
Offsets for its "steps" are 0x2D59-0x2D5A, minus the 2 last bits of 0x2D59. Simply enter any number here to get to corresponding step (don't forget about endiannes and those 2 useless bytes), or change those bytes to "C8 00" to get to the 50th step. Beat it and you'll get your latiasite (plus you'll have 100% chance to catch latias if you have 2500 coins to spend) !
If that's clearrer for you :
->take the (decimal) number of the step you want to challenge and convert it to binary
-> move it 2 bits to the left (add 2 0s on the right)
-> convert it to hexadecimal and read it backwards (endianness)
-> copy that number to said bytes.
Oh, and even better : when you skip steps like this, beating the next step will automatically give you every reward you should have had for previous steps ! Try changing thoses to bytes to "FF FF" (should be "9C 0F" if you don't want any overflow, but it doesn't seem to change anything IG) and beat step 999 (you may need a bit of items for this one), and you'll unlock every single reward available for this challenge (basically there aren't any reward past step ~200) !
Edit: It should look like that for the 50th step :