This article is about one particular step of the procedure for “flashing” a new android-compatible operating system onto a Samsung device to create a Freedom-Respecting Smart Phone or Tablet.


This is about flashing a custom operating system ROM in a Samsung Android device using the tool named Heimdall.

We may encounter a failure mode in which heimdall detect succeeds but heimdall flash and heimdall print-pit both fail, printing this:

Initialising connection...
Detecting device...
Claiming interface...
Setting up interface...

Initialising protocol...
ERROR: Failed to send handshake!ERROR: Protocol initialisation failed!

Releasing device interface...

Additional diagnostics if we give the --verbose option:

"ERROR: libusb error -7 whilst sending bulk transfer"

(This message is repeated several times, before the final failure.)

Errors like this have been reported many times: e.g. here and duplicates, here, here

Here are two scenarios in which this error can occur.

Scenario 1: Only The First Heimdall (Flash, Print-Pit) Command Works

It is reported that on some devices, including Samsung, only one Heimdall command can be given in the bootloader mode. Further attempts fail. Rebooting is required before another command can succeed.

(In this description, “heimdall flash” and “heimdall print-pit” count towards the limit of one command, while “heimdall detect” doesn't count towards the limit and can be used freely.)

This may be a real limitation of the devices, or it may be that using Heimdall's options “—no-reboot” (on each command) and “—resume” (since 1.4.0, on subsequent commands) options may overcome this. I do not have such a device and did not find conclusive evidence in my search for information.

Scenario 2: Every Heimdall (Flash, Print-Pit) Command Fails

This happens only when running Heimdall on certain linux distributions, notably Ubuntu.

Some people fixed this in their forks of Heimdall, e.g. Jesse Chan's fix is in Grimler's version of Heimdall and in several other forks. (This fix works by resetting the USB device on the Linux end.)

My suggestion: build and use Grimler's Heimdall. I explain a bit about Heimdall and how to build and use it in my article Odin and Heimdall: Free Your Samsung Android .

Scenario 3: Heimdall With Resume Option Fails First Time

If the first Heimdall command after booting into download mode is given the '—resume' option, Heimdall fails for me (on Ubuntu 22.04) like this, even when using a version with the Scenario 2 bug fixed:

$ heimdall print-pit --resume --no-reboot --verbose
Beginning session...
ERROR: libusb error -7 whilst sending bulk transfer. Retrying...
ERROR: Failed to begin session!
Releasing device interface...

From what I can tell, this seems to be expected, and so a usage error. The '—resume' option should not be used on the first command.

#fossGadgets #android #degoogled #lineageOS #eOS


This is about buying a Samsung Android tablet and replacing the privacy-invading proprietary Google and Samsung software with privacy-respecting Freedom Software: “degoogling” for short.

Why? In “The Problem” section below, we take a look back at how much we're giving up when we accept Google's and Samsung's terms.

I would like ordinary people, with a little technical skill, to be able to do this. The process unfortunately is currently far too difficult, especially so on Samsung devices.

My goals:

  • Install a privacy-preserving freedom-software operating system on my tablet
  • Make it easier for others to do the same

As I wrote before, My smart watch is open source. Awesome!


Let's make this fun — for children in particular — and show how we can bend the device to our will because FOSS means it's truly ours, fully under our control.


Are you asking yourself,

“What's it to be: Android or iPhone?”

Actually, NO! There is another way.

Time I Learned: there are freedom-respecting phones.

I'll tell you which one you need.

What's the problem?

What's so bad about choosing either Google or Apple?

It's about who controls our use of the device after we “bought” it. Do “they” remain in control of what we do, or are we in control?


From: Google

Your Google Account will soon be considered as inactive

”... if you don't sign in soon”

“Is this a phishing scam?” was my first thought. But no, it's true! This officially confirms I am freed at last from Google's clutches on my data, on my digital life.


I once thought Google was my friend. The most convenient email, the most convenient search, a great phone, with a feeling of being quite open-source-y, not too locked-in. But of course their lock-in is immense, almost inescapable, just like all the other Big Tech silos. Once disillusionment set in, it was hard to leave that all behind. Took me five years.

Now, for months and months I haven't signed in to my gmail, to play store, to youtube, nothing.

And I feel great!

Want to know more?


We'll soon have smart electricity and gas meters. Let's monitor them locally through our home automation system, Home Assistant.


“All I Want for Christmas is...” a device that works as a tool for me not as a tool that continues to work for its maker

We love a new tech gadget. What will it be? It's all about “smart” these days, but when they say “smart” they usually mean “we're still in control of it”.

Learn how you can have a freedom-respecting

  • smart watch (full article)
    • ensuring You (and not They) are in control of your watch
  • smart phone (full article)
    • ensuring You (and not They) are in control of your personal communications
  • smart home (full article)
    • ensuring You (and not They) are in control of your IoT doorbell, lights, sockets, security cameras
  • or even a smart soldering iron (full article)
    • because you can!

My smart watch is open source. Awesome!

PineTime from Pine64 (product | shop | wiki)


Automating our lights, security cameras, all the Things? We'll be needing some IoT Gadgets and a home automation system.

“Which brand? Amazon Alexa or Google or Apple HomeKit?”

NO! Big Tech makes technology that best serves Big Tech. We don't have to accept it, once we learn there's an alternative.

Time I Learned: our smart home can respect our freedom.