I was wondering if I could get some advice on this roasting issue that has been driving me crazy for the past couple months. I got these very sweet/fruity beans (Mexico Ejidos San Fernando Geisha Honey), that were absolutely amazing the first time I roasted them. However, ever since the first roast I've never been able to come remotely close to getting any of the fruity notes of that first roast. This has now become my white whale, I have no idea where I am going wrong.

Here is the protocol I am using with a gene cafe. Note that the following temperatures are the built-in external temperature readings/settings from the roaster.
1. Pre-heat the chamber to 400 F/204 C
2. Add 230 g of beans.
3. Set temp to max (482 F/ 250 C).
4. Around 30 seconds after first crack (which typically starts around 10-11 minutes into roasting) bring the temperature down to 428 F/ 220 C
5. 30-90 seconds later, stop the roast place beans in fan-cooled basket.

I have tried varying the time I wait to drop the temperature after first crack and how long I roast for at this reduced temperature. However, I have only achieved under-roasted coffee that has strong vegetal notes, a not so great light/medium roast that has a tiny hint of fruit sweetness, and a burnt tasting dark roast.

If anyone has advice on this I would really appreciate it.

Maybe it is not the roast, it might be that just your green beans went stale. How are you storing them? I experienced quicker staling especially with honey processed greens and inappropriate storage conditions might let them age them fairly quick.

These beans were in a plastic bag away from light in a warm/dry environment. The green beans still have a sweet/fruity aroma, and I have attempting my roasts about once a week, so I would be surprised if they went bad that quickly.

See if you can get them yellow in 4:00 and 1C in 8 minutes. 10-11 is a bit long. Use less beans if you have to. Drop the heat a bit right after yellow and again about a minute before 1C starts.

And to follow up on what Alan mentioned, don't cut heat back after 1C, try keeping a stable ET till finished.