updating old softmod and trying to get up to speed tsop flash?

been along time since i have messed with the old og xb, a friend originally set this thing up back when this was the current console. got me into learning how to do this kind of thing with other machines since. i have been spending a bunch of time reading threads and watching some yt guides but cant seem to nail down what to do and i dont want to regress or brick my box if i can help it lol .. anyhow..

this is a rev 1.0 xbox had evox as the dash and whatever the softmod was. i so far got the rocky5 extra disc and installed the softmod updates that were included on that iso. i plan to upgrade the hdd to probably a 1 or 2 tb drive with the sata adapter and 80-wire ide.

so i decided next thing to do would be a tsop flash which is where im kinda stuck. i have soldered the proper points for my eprom chip however now im trying to understand the flashing process, as well as what to flash. i keep finding legacy guides of things that i think have been replaced or updated. so looking for guidance on what is the most current bios and (if possible) where to get it and lastly some understanding of how to install it.

it looked like some if these would just install off of a dvd but is there supposed to also be some files prepped to the hdd as well?

thanks for any help