Suggestions
1. What version of xbox do you have? If it's 1-1.5 then either FlashBIOS 3.0.1 or 3.0.3 should work. By default, the chip comes with 3.0.1 on Bank1 and 3.0.3 on Bank2.
2. On the non-working 4 chips, if you've tried both Banks already then I'm guessing that you have xbox version 1.6 or 1.6b or later. FlasBIOS 3.0.1 will only work on 1.6 and 3.0.3 will work on 1.6b and later. So do find out out what version of xbox you have.
3. Can you confirm that the only working chip you have at the moment already comes up with message "Xecuter rox my box"? If so then you might have obtained the chips second hand???
4. Sounds to me like you'll need a programmer to reflash your other 4 chips since you can't do a hot swap. Some information on the programmer. It doesn't run on batteries but instead will plug directly into your PC parallel port. You'll need to supply power to the programmer using the PC USB port. Also, you'll need to connect the chip to the external switch (Bank1, Bank2 etc) and haev it switched to "Flash Enable". Download the program FlashBIOS Manager from
www.teamxecuter.com and follow Sticky tutorial on "Programming the 2.6CE Tutorial". Since you're flashing the chips using the Programmer, you might as well put 5035 on Bank1 and either 3.0.1 or 3.0.3 whichever ones work. If you experience any problems with the programmer, simply punch the error message into Google. That's how I found my mistake working with the Programmer.
5. Once step 5 is completed, put the chip back into the box and see if you can boot on Bank1 or not. Should not be a problem if you had done step 4 properly. Also check that you can boot to FlashBIOS on Bank2. This way you'll know that you have a backup BIOS.
Good luck.