Libsibo on The Last Psion

ASIC4 Extended Mode Addressing

Sat, 04 Apr 2026 00:00:00 +0000

Who wants a deep-dive into a tiny aspect of Psion SSDs and their ASICs?

I was using a PsiDrive a couple of months ago to dump a 2MB SSD. However, when I tried to extract the files, my FEFS extraction tool (siboimg) segfaulted halfway through. So, as I was in a rush, I decided to come back to it another day. Yesterday was that day.

My first thought was that it could be a problem with the Pico 2, either with the code or the RP2350 A2 stepping chip. So, a couple of days before, I built a second PsiDrive and put in a Pico 1. But the fault remained with with Pico 1.

A Long-Overdue Update - PCBs, Emulators And More

Sun, 13 Aug 2023 00:00:00 +0000

It’s been a while, hasn’t it?

My work on this project has been relatively sporadic over the past 12 months. I’ve not found it easy to find a balance between this, my day job, and other projects I’m working on. As a result, there have been some relatively intensive periods of work on Psion shenanigans, followed by burnout or other priorities needing to take precedence.

`libsibo` - Talking to SIBO Peripherals using Arduino

Thu, 07 Jul 2022 00:00:00 +0000

Finally, it’s here! Some proper code for reading SSDs and (eventually) other SIBO peripherals.

I’ve spun off some the Arduino code from SIBODUMP, added the FlashFS code from SIBOIMG, ported it to PlatformIO, and pushed it to GitHub.

So, the TL;DR is:

Two major bugs squished.
It works with more boards now (Pico, ESP32, Arduino Nano)
It’s still uses the Arduino libraries, but it’s now based on PlatformIO
You’ll need level shifters for 3.3v (I’ve included an example)
Would regular Raspberry Pi compatibility be useful?
Next steps
Discord chats

So, take a look at the code over on ~~GitHub~~ Codeberg, then read on.