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New fun fact!

Welcome back!

A few weeks ago Mr. M.P. write me an email with the question: May it possible to drive two TPMs on one Pi (4)?

Mr. M., want to drive one native TPM for the Pi and a second TPM as a remote vTPM for a client application.

So i've tested the Hardware Setting for Mr. M., after a few Minutes and combine this two posts:

Here the results:

Electrical- and mechanical-setting:

Hardware configuration of the two TPMs:

and you'll need 2 TPMs, with one 0Ohm Resistor on position CS0. [1]

Linux log

I hope this will be helpful for you, too.

Bye for now!


Categories: TPM

A new project is online!

Hello and welcome back!

Today I'll introduce you to a new TPM project.

Pierre Fontaine combines a Raspberry Pi, Yocto and a TPM.
He invested a lot of time on his project and I'll appreciate his work with a blogpost here, here is a qoute from his website:

The Raspberry, Yocto Project and The TPM!

In the cybersecurity field we need to play with crypto primitives. It allows us to authenticate for services (ssh, vpn ...), encrypt files for confidentiality, sign mail for proving your identity to the recipient, and even securing the boot of a complex device ...

So you do need to store keys and use crypto algorithms such as RSA, ECDH, AES compliant with some criteria (industry, military, medical ...).

Thank you Pierre to share you knowlage!

Here is the Link:
Raspberry Pi, Yocto and a TPM

By for now!


[1] © Copyright 2019. Jerome Blanchard, Romain Brenaget and Pierre Fontaine

aws iot greengrass with TPMs

Welcome to the November of posts,

Today: Using a Trusted Platform Module for endpoint device security in AWS IoT Greengrass!

The credits goes to:
The Infineon guys for build an example for use a TPM and pkcs11 in an AWS IoT greengrass environment and share it on github[1].
And Krishnan Ganapathy from amazon web services writes a blog article about it[2].

Thanks for the great work!

Bye for now!



Categories: TPM

Move LetsTrust-TPMs to CS0


The last time i get some questions about the chipselect configs for the module.

How you could move the default config from the LT-TPM CS1 to CS0.

If you want to use the TPM with CS0 you must change (resolder) the position of the 0Ohm Resistor to the open pads.

You'll see the difference if you open both pdfs:

If you don’t want to compile your device-tree-overlay by yourself, copy the tpm-slb9670-cs0.dtbo [1] to /boot/overlays/ and load the dtbo in the /boot/config.txt
over the setting dtoverlay=tpm-slb9670-cs0

If you want to decompile change and recompile the devicetree for the slb9670 for yourself:

1) sudo apt-get install device-tree-compiler
2) dtc -I dtb -O dts -o /mnt/boot/overlays/tpm-slb9670.dts /mnt/boot/overlays/tpm-slb9670.dtbo
3) cp mnt/boot/overlays/tpm-slb9670.dts /mnt/boot/overlays/tpm-slb9670-cs0.dts
4) dtc -I dts -O dtb -o /mnt/boot/overlays/tpm-slb9670-cs0.dtbo /mnt/boot/overlays/tpm-slb9670-cs0.dts

Bye for now!



PS: this will only work on the Raspberry Pis 0-4
Categories: TPM

Hardware update!


I've updated the pcb-design,[1]

Now we have the revision 2.2!

Changes from rev 2.0 to rev 2.2 [2]
Add 100nF capacitor on the RESET line of the TPM for a better POR (Power On Reset) behavior..
Change pad 1 from octagon to square, for better identify pin 1.
Add tiny labels on every pin on the bottom side (without MISO/MOSI/CLK, no place for the labels on these pins)

I added a legend in the schematics, for better reference if you want to use the TPM on your own Hardware design.

Placement and the schematic you will find in the right column.

Bye for now


[1] two months ago
[2] Revision 2.1 was never produced.