This forum in general appears to be unmonitored by Bouffalolabs. Pretty sad first impression to leave on people trying to build products around their devices, eh?
While the Bouffalo development boards were pretty nice, they're usually not strictly required. (This means there's probably a business opportunity here for someone willing to spin up some PCBs, too...)
Bl602 is available in plenty of low-cost boards, like the Pine64 PineCone and PineNut or the DOIT BL-10. (They're pretty close cousins to an ESP32-C3 for competitive analysis.) BL604 is pretty much the same device, "just" with more GPIOs. I wouldn't be surprised if they're not the same wafer, just with more pins bonded out. So you could do most of your breadboard/perfboard class development to bring up on a $3 BL602 and move to BL604s when you spin your PCBs.
For BL702 bringup, I'll give a nod to the SiPeed M0Sense for a low-end SBC-like experience with buttons and screen, but for development, the ringer is the Sipeed $3.50 "RV-Debugger". It's USB on one side and 8 GPIOs on the other. Those GPIOs can be programmed as UART, JTAG, or you can drive WS-2812's or whatever else you'd do. You can do all your code bringup and a lot of the hardware development on these tiny boards before laying out your own. I haven't personally tried the "BL702S Development Board", but it looks similar, but with Zigbee and mroe pins.
The BL706 media board is pretty nice, but they've been super hard to get and I haven't seen an equivalent in the wild.
Stepping out of SiFive and into T-Head, we hit BL616. Our recurring main character Sipeed offers the M0S module and M0S Dock. These are approximately the Espressif module with all the high-speed stuff + RF on one PCB or a package much like the JTAG debugger above with USB on one end and 8 GPIOs on the other.
For BL808, my choice dev boards are Pine64 OX64 or (surprise!) the Sipeed M1S Dock. You can get them with our without screens and cameras, but you can again get all your startup code and main I/O up on a reasonable 2.54mm package that brings out SPI, I2C, GPIOs galore and such. These are approximately an ESP32-S3 DevKitC package, but with the weird three core mix.
The Sipeed boards provide schematics and gerbers and all that and I think are all under a free license so you can start from those in your design. They're rarely more than the chip reference designs anyway.
This is an area where the Espressif ecosystem just embarrasses Bouffalo. They make several different boards - that are easy to get from reputable sources in most any country - and encourage others to do the same. Developers trying to evaluate chips for designs should be able to get them easily and quickly. Being able to just reach into my parts drawer and evaluate a QSPI vs OSPI implementation of the same chip on a breadboard instead of waiting for weeks to even be contacted for shipping info is not cool.
I'm not associated with Sipeed or Pine64, but those two companies probably ship most of the boards that are actually used to evaluate Bouffalo parts. There are many open source repos that cover them and you can order them from chip vendors like Digikey or Mouser; they're not some super obscure vendors.
I've developed some on all the chips listed above and all the boards I've recommended. BL makes some interesting chips - and admittedly, some weird ones - but they really could do better attracting developers with appealing eval boards (PineCone, for example, requires moving a physical jumper to flash it because they saved the cost of two transistors to to drive the reset and enable lines that are so well known in the ESP32 world...so maddening!) that are easy to get, easy debuggers (I think the BL706 board used three chained adapters...), sensible toolchains (I've lost track of which SDK is 'live' any more), good support (way too many unanswered questions here) and good doc.
For the kind of people that read boards like this, there may be a minor business opportunity here. It's been three years since BL706 Audio Video Board was teased, but they've never really been available in the wild, for example. Look at the specs for something like the ESP32-S3 Box or ESP32 Kaluga and see if JLCPCB (or whomever) can splash down a BL706 module, some headers, a normal JTAG socket, some buttons, screens, headers, and all that and just sell them. If you're capable of building such a board, you probably already ARE the market for what development boards should have, so your market research is easy - it's you! :-) But competing with Sipeed, Pine64, and potentially, Bouffalo themselves in case they decide to flesh this product line up and actually start selling these boards on Ali or Digikey or whatever could be a tough life.
But this really seems like a market that Bouffalo should be driving themselves in order to drive chip sales...
Anyway, for those above that are trying to actually get hold of hardware to do some coding or soldering, hopefully there are enough leads here for alternatives to get you going.
