GQ4X is the burner i use and would recommend it. I think the newest model is now called GQ-4x4. GQ4x will program 25Vpp needing chips like 2532s which many of the cheaper burners can't do.

W27C512 is great chip for the nvram.weebly MPU U1 location. Electrically erasable instantly by the burner, cost usually well under $1 each, i haven't had a dud one yet out of hundreds, and they are widely available from Chinese sellers on ebay/aliexpress.

If you install a ROM into the U1 ROM location of the nvram.weebly MPU, remove the U2 enable jumper shunt (or the u2 chip itself, but easier to just pull the jumper shunt out).

I love meteor but damn the background sound is brutal when it hits the 2nd time through the scale and there is a constant high pitch dog whistle like noise constantly. If its not easy to turn off/on maybe tone down the super high pitched part when it rolls through the levels a 2nd time.

I think its triggers a "non maskable interrupt" that sends the CPU off to do stuff. In the test mode the software is probably not able to jump back to display test when NMI is pushed at that point. I noticed some bally games will report switch zero is closed if you push the NMI in switch test. I think its just later games, and maybe even just hacked ROMs.

Same kind of thing happens in MPU200 games if during attract you push the NMI button before the test button. Software crashes instead of going into test mode.

I'd encourage anyone that wants to try out custom ROMs to get an EPROM burner, they are pretty cheap and the reusable chips can be as low as $0.50 (recommend W27C512). While i have not updated the combo rom of the weebly board since 09/17/21 I will try and update it soon with all the most recent combo ROMs I can find. I don't really want to sell individual ROM chips for various reasons including licensing of some brands

For a Weebly MPU before they started using a single universal rom and dedicated U1 expansion ROM slot, custom ROMs can still be run out of the U2 socket. You will need to format the files.

Download Slochar's files. Rename the 16K files to U1.716, U2.716 U5.716 and U6.716

open note pad and paste below in. Save it as a .bat file in the same directory with the ROMs. (you might have to turn on file extensions to rename .txt files to .bat).

copy /b U1.716+U2.716+U5.716+U6.716 U2COMBO.764
copy /b U2COMBO.764+U2COMBO.764 U2COMBO.128
copy /b U2COMBO.128+U2COMBO.128 U2COMBO.256
copy /b U2COMBO.256+U2COMBO.256 U2COMBO.512

Run the batch file, and it will spit out four files depending on the ROM type you want to use. U2COMBO.764 for 2764 U2COMBO.512 for w27C512 and etc.

For later nvram.Weebly MPUs with a universal ROM and a dedicated U1 rom spot, I believe slochar is packing in a U1 burn ready file. If not you can create one from the 2716 sized files and a copy command. The FF file is 2716 sized ROM that is blank. You can create with your eprom burner software by doing a read of a 2716 ROM with no ROM inserted in the burner. It should return all FFs. Then save it as FF.716 with the other ROMs you want to combine.

copy /b FF.716 + FF.716 + U1.716 + U5.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + U2.716 + U6.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + FF.716 + U2.716 + U6.716 U1.512

When using the U1 ROM spot you need to turn off the U2 universal rom by pulling out the "U2 Enable" jumper shunt near the universal.