Hi @Irish! Are you trying to accomplish running animations without a computer? I bought a similar kit (iCubeSmart 8x8x8 on Amazon), and I'm stuck at the point where tomazas' project can control my Cube, but only an entire column at a time (lighting any individual LEDs causes the entire vertical column to light up).

I already was able to create a simple C# program to talk to the cube via Serial, but I am limited in my creativity until I get the cube fully working.

If you're familiar with Java or C#, then you could also program the cube that way.

@Sid Grover I happen to have a Chinese program from the manufacturer (not sure if you have the same product as mine) used to flash the .hex firmware onto the chip (https://drive.google.com/file/d/1a62NuU_QtyUHD0oo4XSAAWj_dZoWQHCB). You should double-check the schematics and photos. What also helped me was setting the Min and Max Baud rate to 9600, making sure the cube had RX, TX, and Ground connected but NO 5V, pressing Download, and THEN powering the 5V connector. And yes, for my board too, I had to connect RX -> RX and TX -> TX.

My goal is to get this cube to work with tomazas firmware, and then build a music visualizer app that talks over Serial, among other things in C#.

I too am in the same situation except I have gone further and bricked my cube by trying to load one of the codes, 8x8x8.hex, from GitHub. Using the STC-ISP tool. Everything seemed to go well and according to the tool uploading was a success but all the cube did after was buzz from the speaker on the board. I don’t have the same cube as in the picture here but it uses the same STC12C5A60S chip. I have searched the web for information on what to do but find almost everything confusing as I have no programming skills whatsoever however I am determined to get my cube going again and to that extent I have ordered 4 more chips from Aliexpress (they are as cheap as chips, 4 for £6, lol)

 One very strange thing is that all over the web everyone says to connect the RX-TX and TX-RX on the USB-TTL cable but my chip is not recognised.  It is only recognised if I connect RX-RX and TX-TX.

So now the STC-ISP tool still recognises my STC12C5A60S and still claims to successfully download HEX codes to it, such as ledcube8.hex but nothing happens.
Am I missing something here? I have another cube coming, as I really loved making my last one so I plan to swap the STC12C5A60S chip from it to my bricked cube to confirm that everything else is ok with the cube such as the shift registers and all the other components on the board. If all is well with the bricked cube after putting the chip in from the new cube I wonder if I can upload the code from it and reinstall the code onto my bricked chip.

One day my bricked cube WILL be working again, I am determined.
For anyone interested, I didn’t like the messy look of the way most people on YouTube soldered the LED’S together so I copied what another guy did and made a jig consisting of a 5mm hole in a piece of MDF with a pin driven into it either side of the hole, the pins being a touch larger gauge than the LED legs, and wrapped each leg round the pins. Then I got some 30 amp fuse wire, straightened it in a drill. This I copied from YouTube but modified the procedure because I couldn’t be bothered to cut 128 pieces of wire and straighten each one so I fixed one end of the wire to a tiny hook screwed into a doorframe and walked across the room with the reel, cut the wire placed the end in a drill and managed to straighten 34 pieces at a time. Each LED was slid onto the wire so that all my lines are perfectly straight both horizontally and vertically ending up with a perfectly formed cube. 

Another thing, after I bricked my cube my windows 10 laptop crashed and could not be restored via any method. I ended up moving all my files to another drive and installed a fresh copy of windows. Kaspersky warned me that the STC-ISP download was a Trojan but I ignored it because I thought Kaspersky didn’t realise that the STC-ISP was harmless however it seems that more than a few of the downloads for this tool do indeed have Trojans in them , even one I downloaded from a very reputable source so be careful if you download this file stc-isp-15xx. I have a clean copy now but still Windows smart screen doesn’t like it because it is not recognised but Kaspersky is happy with it.
I wonder if this episode has anything to do with my bricking of my cube?
I hope this helps anyone in a similar situation to me

I feel your pain, as I am in exactly the same position as you. I am about to try communicating with my cube, but if I erase it's original program, it's bricked as a stand alone unit.

I saw on Github something about "original Chinese software" so presumably both people like me, and those who got a kit with an un-programmed  chip in, (and those that blew up their chip, replacing it with a new one) should be OK. From there it seems a fairly simple matter to modify the pattern and check it will load and do that, as a stand alone.

After that, adding a whole bunch of custom patterns would be the next step. Having 60k to play with, should be enough for some awesome displays. I am guessing that you could just tag on a large sequence, into the original software. If you have made any progress, please post an update. I will too, if things go according to plan.