Some information on RGP indicates that the boot flash rom is U7 - which is buried inside the RCT file from stern in the 'pinball' folder.

AFAIK whitestar images are just burn on the correct eprom and go. It boots with the older code still?

What is the file size of the ROM and what is the ROM size you are trying to burn?

If the EPROM chip is bigger than the binary file, you need to fill the ROM chip with repeated copies of the binary file. If the binary file is bigger than the EPROM chip you need a new bigger EPROM chip.

it uses a 27c4001 for display and a 27c1001 for cpu

The CPU rom size is 128k so you need a 27C1001 or 27C010 to burn the file directly.

You will need to quadruple up the rom file for your 27C040 or double it twice.

I create batch files to run command prompt strings to combine ROM files.

Example turning 27c010 image file into 27c040. The starting file will be a 1mbit (27c010) in size and named ROM.1MB for example.
Fire up windows program notepad and copy the single line below into it.

copy /b ROM.1MB+ROM.1MB+ROM.1MB+ROM.1MB ROM.4MB

Save that notepad file as COMBINE.BAT (the .bat at the end is important, it can't be .txt or whatever) in the same folder as ROM.1MB
Run COMBINE.BAT by double clicking on it and it should create a quadrupled up image ROM.4MB.

Some eprom burning software has ways to fill up a larger eproms. For GQ-4X you can set device to to 27c010. Load the rom. Select all and Copy. Set device 27c040. Select all and delete. Then use the paste command four times to fill up the 4x larger EPROM.