Flashing with evox is fine. Just make sure your evox disk has the flash chip/tsop option on it You may have to edit your evox.ini file and reburn the cdrw with the added 4983 bios and rckey data. Should look something like this: Follow the GREEN COLORED LINE
PUT YOUR BIOS NAME INTO quotations
ROM = "4983",0x123456789abcedfghijklmn (ETC.)
If you dont know the rckey data use xbtool (found on xbox scene) and then open your bios and the rckey data should look similar to the bottom data here.
You should have no problem flashing then, since your modchip will have a generic flash chip that is equivilant to the chips found on the xbox. Just make sure your edited line has the same format as listed below.
[BIOS]
#
ROM = "EvoX M7",0x93db270779f5b964f50be075a5d5d2d2
ROM = "EvoX M7 ef",0xf0980189407abca8d1f8d823621beaf0
ROM = "X2 4977",0x92987e26edd5833921c9b0e539ea091e
ROM = "X2 4978.03",0xe432af482dd624427fc3cf6ce2589489
ROM = "Original 3944 1MB",0x542c62cb976a4993c8c5027dff9638ce
ROM = "Original 4034 1MB",0xF20CD7574BB4B2A69810B2E9F766A90
ROM = "Original 4132 1MB",0xcf36ad116e2404aff022533b07b11004
ROM = "Original 4817 1MB",0xc3db66c8e212974afec6d6087ddbb8ef
ROM = "Original 5101 256k",0x769898e9682e1f5d065b5961460d03e6