OsmoDevCon 2024: "Detailed workings of OTA for SIM/USIM/eUICC"

I've presented a talk Detailed workings of OTA for SIM/USIM/eUICC as part of the OsmoDevCon 2024 conference on Open Source Mobile Communications.

Everyone knows that OTA (over the air) access to SIM cards exists for decades, and that somehow authenticated APDUs can be sent via SMS.

But let's look at the OTA architecture in more detail:

OTA transport (SCP80) over SMS, USSD, CellBroadcast, CAT-TP, BIP

The new SCP81 transport (HTTPS via TLS-PSK)

how to address individal applications on the card via their TAR

common applications like RFM and RAM

custom applications on the card

OTA in the world of eUICCs

talking to the ECASD

talking to the ISD-R

talking to the ISD-P/MNO-SD or applications...

OsmoDevCon 2024: "Anatomy of the eSIM Profile"

I've presented a talk Anatomy of the eSIM Profile as part of the OsmoDevCon 2024 conference on Open Source Mobile Communications.

In the eSIM universe, eSIM profiles are the virtualised content of a classic USIM (possibly with ISIM, CSIM, applets, etc.).

Let's have a look what an eSIM profile is:

how is the data structured / organized?

what data can be represented in it?

how to handle features provided by eUICC, how can the eSIM profile mandate some of them?

how does personalization of eSIM profiles work?

There is also hands-on navigation through profiles, based on the pySim.esim.saip module.

You can find the video recording at https://media.ccc.de/v/osmodevcon2024-174-anatomy-of-the-esim-profile

Neural Networks (MNIST inference) on the “3-cent” Microcontroller

Bouyed by the surprisingly good performance of neural networks with quantization aware training on the CH32V003, I wondered how far this can be pushed. How much can we compress a neural network while still achieving good test accuracy on the MNIST dataset? When it comes to absolutely low-end microcontrollers, there is hardly a more compelling target than the Padauk 8-bit microcontrollers. These are microcontrollers optimized for the simplest and lowest cost applications there are. The smallest device of the portfolio, the PMS150C, sports 1024 13-bit word one-time-programmable memory and 64 bytes of ram, more than an order of magnitude smaller...

OsmoDevCon 2024: "High-performance I/O using io_uring via osmo_io"

I've co-presented a talk (together with Andreas Eversberg High-performance I/O using io_uring via osmo_io as part of the OsmoDevCon 2024 conference on Open Source Mobile Communications.

Traditional socket I/O via read/write/recvfrom/sendto/recvmsg/sendmsg and friends creates a very high system call load. A highly-loaded osmo-bsc spends most of its time in syscall entry and syscall exit.

io_uring is a modern Linux kernel mechanism to avoid this syscall overhead. We have introduced the osmo_io`API to libosmocore as a generic back-end for non-blocking/asynchronous I/O and a back-end for our classic `osmo_fd / poll approach as well as a new backend for io_uring.

The talk will cover

a very basic io_uring...

Decapsulating the CH32V203 Reveals a Separate Flash Die

The CH32V203 is a 32bit RISC-V microcontroller. In the produt portfolio of WCH it is the next step up from the CH32V003, sporting a much higher clock rate of 144 MHz and a more powerful RISC-V core with RV32IMAC instruction set architecture. The CH32V203 is also extremely affordable, starting at around 0.40 USD (>100 bracket), depending on configuration.

An interesting remark on twitter piqued my interest: Supposedly the listed flash memory size only refers to a fraction that can be accessed with zero waitstate, while the total flash size is even 224kb. The datasheet indeed has a footnote claiming the same....

Cynthion Manufacturing Progress

Note: This is a crosspost of a Cynthion update on Crowd Supply: https://www.crowdsupply.com/great-scott-gadgets/cynthion/updates/cynthion-manufacturing-progress

Cynthion update time!

Final samples have been manufactured, some of them have been sent for RoHS testing (and each of them has passed), and manufacturing is under way. Everything’s going great so far, and we’re on track for June shipping!

Here is your first glimpse of finished Cynthions in their enclosures and in the boxes we will be shipping them in.

The significance of RoHS testing is that Cynthion had to pass that test in order for us to earn our CE marking, which allows us to sell Cynthion in the...

Introducing the Bantam Tools NextDraw™

Bantam Tools proudly unveils its latest advancement in proven plotter technology with the launch of the new Bantam Tools NextDraw series of drawing and handwriting machines. Engineered for artists, innovators, and educators seeking exceptional versatility and performance, Bantam Tools now offers a trio of new models designed for drawing and handwriting.

“The Evil Mad Scientist team have brought their engineering prowess to Bantam Tools and the new Bantam Tools NextDraw series are proven creative tools that set a new standard in plotters. The Bantam Tools NextDraw series of plotters are exceptional computer controlled machines for innovators.” says Bre Pettis, CEO...

An interview with Interaction Designer Arthur Carabott Part I

An interview with interaction designer Arthur Carabott who describes how he came to work on the Olympics and how he ended up moving from London to LA.

The post An interview with Interaction Designer Arthur Carabott Part I appeared first on Music Hackspace.

New Products – Spring 2024

As always, the Crystalfontz team has been working to bring you new and exciting display solutions. This update includes a family of modules designed to integrate with the Raspberry Pi CM4, some transparent LCDs, a family of 2.8″ TFTs, and a few updates to products to ensure long availability with minimal design changes required.

New to our product line are two beautiful displays designed to work quickly and easily with the Raspberry Pi Compute Module 4. These displays are crisp 5″ displays with 720×1280 resolution and in-plane switching (IPS). These modules include easy mounting for compute module,...

Implementing Neural Networks on the “10-cent” RISC-V MCU without Multiplier

I have been meaning for a while to establish a setup to implement neural network based algorithms on smaller microcontrollers. After reviewing existing solutions, I felt there is no solution that I really felt comfortable with. One obvious issue is that often flexibility is traded for overhead. As always, for a really optimized solution you have to roll your own. So I did. You can find the project here and a detailed writeup here.

It is always easier to work with a clear challenge: I picked the CH32V003 as my target platform. This is the smallest RISC-V microcontroller...