I flashed my Xbox v1.0 with Xecuter FlashBios v3.03, after realizing that I had flashed it with the wrong file, I tried to reflash it via FTP using Xecuter2_4976_Multiver_256k, and then via DVD, but I keep getting " Unkown flash ! Halting" , is there a solution for this problem besides a modchip ? Should I be trying to use another bios version ? Can I use the solderless Xecuter 3 to reflash the TSOP and then remove the modchip ?

If you boot it with a modchip, make sure that you disconnect the "D0" **BEFORE** you reflash. If you don't, you would just end up reflashing the modchip. Also, some modchips might be sensitive to power removal, so don't unplug the modchip from the mobo before powering off.

As for which BIOS to use on a TSOP, I would experiment but with a modchip handy...