By 'the benefits of 1.51', I assume you mean the homebrew benefits of 1.50. But yes, 3.80 M33 offers you the benefits of the latest firmware plus the homebrew benefits of 1.50. And yes, you use the 3.52 M33 update first, the the 3.52 M33-4 update, then the 3.80 M33 package. (They're all available from Dark-AleX - PSP Developer, but you'll also need the 1.50, 3.52 and 3.80 official updates - obtainable from PSP Hacks · Hacks, PSP Downloads, Cracks, Mods, Homebrew, Utilities · Hack Sony PlayStation Portable.)

__________________