Not really (opennvr firmware)
What you'll need to do is get hold of the SDK for the chipset, so that you can compile a kernel and app's.
Once you have that, then you can start building firmware and flash.
Issues are that not all hardware is identical, so you will have different NAND types, flash sizes, gpio usage etc.
Not insurmountable, but you'll generally want to pick the same hardware to develop, and port to.
The SDK for the HI3615C is here - http://pan.baidu.com/s/1o8TWZ0Y----
Let me know if you have problems downloading, I can put elsewhere.
Generally speaking, you'll want to open up whatever hardware you have. Add serial headers, and connect up serial for minimal debugging, and for more serious stuff JTAG. Boot up the hardware, and see what it tells you. Hopefully you'll be able to see a boot log and bootloader, and communicate with it.
Developing with just serial is viable though if the hardware isn't too locked.
i.e. hopefully the device will have an accessible bootloader, then you can flash kernels and filesystems without too many headaches.
The flash will generally contain a bootloader (don't overwrite this, otherwise you'll need to use an SPI flasher or similar to rewrite).
The bootloader will load a kernel from the flash into ram, then execute it.
The kernel will then mount a filesystem from flash, and run the OS + programs.
A BSP or SDK allows you to build a kernel and programs (BSP = board support package. SDK = software development kit).
Thats a brief overview.