Before I clarify my question, I will explain the project I'm working on, and what I've done so far so there will be a better understanding of what I'm trying to do. I'm trying to modify the UI of a Roland GR-55 guitar synthesizer so that the UI functions better. To get a view of what exactly I'm trying to do, please view this PDF Firmware layout pdf
So far, I've sent the chip to a lab to have the chip decapped, where optical images were taken of the die markings and circuitry layout. From examining the logo and how it was integrated into the layers, I was able to confirm that it was a Renesas custom SoC. After examining schematics from other products that use the same chip, I was able to find out that the chip's debugger is a Renesas e10a-usb emulator/debugger, which means that the chip belongs to the Super H family. After purchasing the emulator which came with files of all the Super H MCU's schematics, I spent months analyzing the pinouts of all the MCU's until I had a list of the ones that matched my device. From there I was able to identify that the MCU was a Renesas SH2A_custom_SoC1, and successfully connect the emulator to the GR-55 unit. So currently I've been examining the assembly code within Renesas's IDE High performance embedded workshop or (HEW) and you can probably imagine where I'm going with this question.
So from a professional point of view what would be some routes I could take to get this job completed with the desired results, and what variations of time, cost, and resources could those routes have. Here are some of the routes I took into consideration.
Learn assembly language and learn how to modify the code myself. I estimate this could take me around a year or more.
Hire a Reverse Engineering (RE) service. What would be involved with hiring a RE service? Would it even be likely for a company to take a job like this? If they did, what might be a cost and time frame? I understand that it all varies, and one might have to analyze the code themselves to give me an estimate, but I don't know much about RE and I'm trying to prevent myself from being scammed or disappointed with results.
Another option I considered is hiring an engineer to write new firmware from scratch that functions the same way as the current firmware, but has my desired variations. I've contacted many software engineering freelancers and they told me that this would be the only way they would help because modifying the existing firmware would be more difficult than writing one from scratch. I found this hard to believe because the GR-55 does some complex tasks which I wouldn't think could be easily replicated. But could this be a route I could take?
I understand why someone would think a project like this would be a waste of time and effort, but the reasons I have for doing this are specific to me. As a musician, I've owned this device for 10 years and will probably own and use it for the rest of my life, just like I'll own and use my guitar for the rest of my life. I've owned every other device and software that offers similar features and they all suck including the GR-55. I have friends who use this device too, so it wouldn't be just for myself. I've also made it a goal to learn assembly language and C because it's interesting and I believe it's a good skill to learn, so regardless of whether or not this project fails, I will be continuing to learn about RE.