Gota new box??? Omedetou Gozaimasu !
pretty much possible to be jtag friendly
best wiring does not involve ARGON_DATA anymore (rol board) best spot suggested is AUD_CLAMP instead of ROL, the other one stills DB1F1 or any clone, check the JTAG guides if not familiar.
If you ever did a jtag before, you should know better that ROL is deprecated.
if you have a friend with a Jasper with the alternative wiring already, ask for the 1st 80 blocks, flash it instead of Xell (make backups 1st of curse, at least 2 or 3 matching copies), this will give you bad keyvault, take your CPU key, extract your own SMC, customize it, create freeboot with this smc.bin you just customized, y a volar!!!
be warned, it will give a false possitive Rrod though xell will still work.
This will save some time, is a technique I use
DON'T FORGET TO APPLY VERY SAME WIRING TO YOUR BOX IF USING SOMEONE ELSE'S XELL, OR IT WILL E79
you don't need CPU Key from the other box for this to work.