Write Program Blocks in to S7-300 PLC

I'm sure there isn't any official documentation, but is there any resources out there on how to write in OB/FC/FB blocks in to a S7-300 PLC without using programming software? Or rather, is there any official or unofficial documentation on the S7 Ethernet protocol that defines how to read and write to more than just I/Q/M/DB memory? I'm mainly just curious, and since there are a few third party S7 programming tools, I figured there may be something out there.

I have not seen any documentation but this open source library can handle upload/download DotNetPlcToolbox. You will have to examine the source code.

If you have Step7 installed on your computer you could manage download and upload of blocks from a C# or VB.net program via an API to Step7 called command line interface.