Assuming you mean "potential for memtest86+ on UEFI-based aarch64 systems" - memtest86+ takes over the entire system, rather than relying on firmware services. In that respect it's more like a kernel rather than an app, and so involves a lot of architecture-specific setup code - the UEFI port here is more about being able to jump into the memtest86+ "kernel" from the UEFI firmware than making it a generic UEFI application. It also needs guarantees around memory access that aren't provided by C, so there's assembly code to do that. And finally, a lot of the hardware interaction seems to assume a PC-type platform. I don't think there's anything impossible to port to aarch64 here, but it looks like a fair amount of work.