Really nice project – respect :) Finding that boot ROM mode by bridging GPIO lines is a great catch. Having a hardwired 'safety net' makes custom firmware projects much more viable. When you were testing the flasher, did you find the CXD2687's flash interface to be deterministic in its failure modes, or did you run into any race conditions/timing issues during the erase/write cycles?

Thanks! The main problem I had was conflicts with the 'patch' peripheral during the erase/write. This peripheral allows for a small virtual overlay in memory space. It was used in previous devices to fix small bugs by overwriting a couple of words in the ROM. As all the flashing code needs to live in SRAM during flashing, the vector table needs to be patched to point to the code in SRAM. During the erase/write cycle you need to poll the values on certain addresses to figure out success - and if you haven't correctly disabled the patch overlay that can go wrong. That was how I got my first brick :)

Thanks! Does it mean I can now upload tracks to the mz-rh1 without using their ugly piece of software? Or is this still impossible due to the use of cryptographic keys?

The firmware in a sense does not change anything regarding connectivity (for now). If you want to record normal MD, just use Web MiniDisc Pro. For HiMD, I recommend the Electron version of Web MiniDisc Pro, but it's not yet as stable as SonicStage (due to the complixity of Sony's system).

how on earth did you discover this??? Did you reverse it from a dump?

I got similar experience. Using Berkeley DB until I found SQLite ;) Of course it is not directly key/value, but small size, simplicity and IO performance was amazing for me.

I think the same. Really nice project and good trick with hashing tokens.

PS. There left 21 bytes (21 * 0x00 - from 0x01e0 to 0x01fd). Maybe something can be packed there ;)

Nice tool. Do you know maybe similar tool for MySQL ?

Thanks for sharing your experiences :)

You mentioned "harness engineering". How do you approach building "actual programmed tools" (like screenshot scripts) specifically for an LLM's consumption rather than a human's? Are there specific output formats or constraints you’ve found most effective?

Really nice project :)

Thanks!

`git bisect` is interesting option. I haven't heard about it before. Thanks for info. Still learning something ;)

I'm old school. I used to do "manual bisection" on git history by just `git checkout <commit_id>` until I find first introducing bug commit.

Then another "bisection" on commit changes until minimal change found.

Deterministic bugs are quite "fine". For me personally worst are randomly occurring bugs in specific conditions for eg. some race conditions.

Really nice project - respect :)

Got two questions: 1. How fast it can ride ? If I good estimate (based on max 2750 RPMs for electric motor MY1016 350W 36V, gear ratio ~100:1 and height of rear wheel ~0.5m) it should got about 0.8 m/sec. So really safe for kids and dad :)

2. How long does the battery last ?

I think it goes about 6mph. I agree with your maths though, so probably my estimate of the gear ratio is wrong.

I don't know how long the battery lasts, we have never driven it for long enough to flatten the battery.

While I was building it I used it for about an hour doing several laps of dragging a "trailer" full of rubble from the top of the garden to the bottom (the easy direction - empty load on the way back up) and it became noticeably slower towards the end but still got me up the hill. So I'd say it lasts over an hour.

Thanks for info. And once again really nice project :)

Yep, cost effectiveness of project is amazing & really nice application for WSPR. WSPRnet for checking readings seems to be still online https://www.wsprnet.org/drupal/wsprnet/map .

667 - “fax number of the beast” - that was funny ;) The thing about mathematics is that it can tickle your brain - in a creative way.

It's becoming increasingly difficult these days, with so many things competing for your attention and "brain-deadening" you. It was a wonderful thing to be bored and play around with math. My favorite moments were the epiphany - that there is some hidden connection between math areas or something got new meaning.

I had a similar epiphany in college, somewhere amongst Calc I, II, III, DiffEq, physics, and engineering. I kept meaning to pursue it, but life got in the way and I never did. Unfortunately, I can no longer remember what that epiphany was, and I am sad.