Hey Paulo. The process is actually really simple, if you have the means to desolder the flash IC. I'll give the basic no-nonsense outline here, and if you have any questions, let me know.
First step is unfortunately to desolder the flash IC, and connect it to your favorite SPI programmer.
- If you don't have a favorite SPI programmer, or don't own any of them, what you want to pick up is a Bus Pirate v3.6 - sources include Amazon, SeeedStudio, Sparkfun, etc, for around $30. Keep in mind, the Bus Pirate is not the fastest way to do it, but whatever you buy, it needs to be supported by Flashrom. Also, I'd strongly recommend specifically the Bus Pirate v3.6 - older ones are limited in hardware and the new 'better' v4 isn't as well-supported, changes the pin ordering and quantity on the header, and most guides assume you have the more widespread v3.6 (or earlier) design.
Second step is to connect the chip to the SPI programmer.
- Myself, I pulled the chip off and soldered wires to the proper pins (use the datasheet from the chip to match wiring to your SPI flasher) in single-bit mode, which is all the Bus Pirate supports as of when I performed this hack. This means Clock, Data 0, Chip Select, ignore the other Data pins. You'll also need to tie a few of the lines (Write Enable and ...something else, I can't remember right now) to VCC or GND depending on which ones they are, to enable write mode and so forth. If you know about flash memory it's easy to figure out which pins. If not, well, frankly I've forgotten which IC it was, and exactly what pins go where, and my camera is not in a place that's easy to unmount and disassemble. If you can't figure it out, tell me what the chip's part number is, I'll pull the datasheet and provide a complete hookup guide. Sorry, but I go through so many random projects that I lose track of details like that, but I guarantee I can get you the right info if you get me the chip's part number.
Third step is to dump the chip's contents using Flashrom into a backup file, so you don't completely lose the camera if something goes terribly wrong. Again, the info for using Flashrom is out there, specifically there are also some BusPirate guides to using Flashrom, but not with this chip. The changes are trivial.
Fourth step is to write the chip's contents with the EyeSpy firmware, again using Flashrom.
Fifth step is to reinstall the chip and enjoy, because you're now done. The camera's default settings/login/etc are available in the EyeSpy247 RC8221 manual, I found it with a simple Google search. Holy crap is this thing ever a lot more capable than I'd expected.
Sorry for the lack of clear detail, it's been ages and I cycle through random projects in a matter of days. I never keep the details written down because usually nobody really cares how I did it, hah. Maybe I should start a little blogroll of my own.. As I said, if you need more info, definitely let me know. I'm more than willing to help. Just get me the chip's part number.