Looks like the smart one is you.
If I were you I'd tell your brother he owes you a new Xbox 360 and to not take something that is yours and do whatever he wants to it without even knowing what was done.
For all you know they could have gut-swapped your 360 with a motherboard that is going to fail tomorrow.
Damn, I swear, some people just have no clue about things..
As for your question, there's no telling what was done since I, nor anybody else on this forum was there nor were we the ones doing whatever was done to your Xbox 360.
Since it's a BenQ drive, it most likely was firmware modded.
You can take the Xbox 360 apart, and plug it in via a SATA cable to your PC and power the 360 on and if you have a compatible chipset you could open JungleFlasher and it should display the drive on there and show you what version of iXtreme it was flashed with.
Hopefully it was flashed with iXtreme LT firmware, which is the safest out right now.
If you could get the drive key via JTAG if it was by some chance JTAG'd then you could flash back the original firmware.
Advice: Next time don't let things that are yours that you don't want messed with to be in the hands of someone like your brother who obviously you shouldn't trust if he's going to take something of yours and do something with it at a place that he doesn't even know where he got it done at. That's just trouble written all over it.
Oh, and nobody is going to help you with smart ass little comments like you've made. It's not our fault that this happened and it's not our job to help you at all if we wish not to. You can't just magically revert what was done. It doesn't work like that.
Spend more time asking your brother what his problem is and why he doesn't even know where this was done and that it's his responsibility to getting it reverted or else buying you a new console.
Edited by LiarInGlass, 19 March 2010 - 01:10 AM.