How to reset Raspberry Pi B+ to the default version? - raspberry-pi

There is a Raspberry Pi 3 B+ which was already used.
I need to bring it to the default settings, i.e. to the state which you get it from the store (so that I can start using from scratch again, I want raspberry to forget all the previous actions, like it is new. Or simply cancel all the previous actions one has done).
What I did:
I tried to search "how to reset" or bring to the default, I could not find anything. Everything is about factory default and reinstalling some image.
Among useful commands I didn't find: https://raspberrytips.com/raspberry-pi-commands/
Isn't it not simple like resetting a smartphone? I may google differently.

The only way I could find to reset my raspberry pi is to rewrite (reflash) an SD card of it.
https://www.youtube.com/watch?v=ntaXWS8Lk34

Related

IMX8MM Linux: Change Shutdown behavior

I have just started to work in a project where the product uses a imx8m mini module together with Yocto Linux (Zeus).
Currently we have a problem related to the shutdown behavior of the product, and we need to modify what happens during a shutdown.
As today when we shutdown or a thermal emergency happens, the PMIC_ON_REQ(That controls the external power regulator) goes low, but we need to change this behavior that it keeps the current value on PMIC_ON_REQ, as we have other diagnostic devices that needs to talk to the PMIC after that the imx8mm has turned off. In other words: I want to keep the value of the gpio as long as possible, until the control is out of reach.
But my current problem is that I don't know where to start, or what kernel module I shall look into.
Does any one have any clue where I shall start to look to be able to find the code for patching?
I have tried commands in devtool like "devtool modify power/thermal/soc" but without finding the needed code..
Please observe that this is my first Yocto project ever, so if I write something strange, bare with me

Hyperpixel 4.0 strange behaviour of Touch driver error

I since a few months, I have been using a Hyperpixel 4.0 Touchscreen with my Raspberry 3B+ without any problems. Since a few weeks i use my touchscreen with the Raspberry Pi 4 Compute module and mounted both on my own designed PCB. Unfortunately, I’m facing some difficulties with the Touch function of my Hyperpixel 4.0. I have no clue how to solve these problems because the circumstances, which cause the fault don’t make sense to me.
Which System do I use?
Hyperpixel 4.0 in combination with Raspberry ComputeModule 4 with 2GB RAM and 8GB onBoard eMMC. Both is mounted on my custom PCB, which is supplied with 24V, stepped down by an «APP63300WU-7» Step down converter, which provides 3A # 5.1V continuous output. The measured Voltage over 2 Days of measurement is a maximum of 5.2V and a minimum of 5.05V. The software ist the latest Raspbian.
What error is caused?
I have been running a GUI on my Raspberry Pi. I have one Page on which i have three sliders for changing brightness of my room light, colortemperature and one slide is to regulate the speed of some fans. Everything works fine in darkmode, but if I change to lightmode and touch the screen for about 1.5 seconds, the touch- function hangs up. My GUI doesn’t move anymore and I have a still image. I know that it’s only the touch function beacause if I plug in a keyboard and mouse, I can open for example chromium or other stuff without problems. With «i2cdetect »-command I can detect the Goodix GT911 driver on Address 0x14. Even if the touch has hung up, i can detect the Goodix GT911. I know that the address should probably be 0x5D but I thought it isn’t necessary to care about this problem as long as it works. After a reboot, the touchscreen works fine again until i use the lightmode of my GUI. Interesting to mention is, that i can click a thousand times for around 0,25seconds and no problems occur. But if I touch the screen permanently for around 1,5seconds, I instantly get my above described problems. Generally considered, this problems seems very strange to me and it doesn’t behave like any physical law i know…
On the first view, the error seems like a software issue ? Hear this!
If i use the official «Compute Module 4 IO-Board » to mount my Compute Module and Touchscreen, I don’t get the issue at all… My actual designed PCB ist the 2nd version. On the 1st version It also worked fine without any problems. The only differnce between version 1 and 2 is the wiring, which I tried to improve on the 2nd version and viewer parts which I only put on my 1st version to evaluate some functionalities like ethernet or 2nd I2C-Bus, which I’m not using on my 2nd version. The wiring did not change between these two versions, i only tried to increase the distance between the GPIO-traces to improve signal integrity.
So it seems like a hardware problem? But why does the GUI work fine in darkmode? I don’t have any explanation to that.
What did I do to narrow down the error?
I flashed a new image on my Compute Module and also used another Compute Module, Custom PCB and touchscreen as well, but without any success. As far as I experienced, the issue is only caused on my GUI and not on any other websites or images, etc. An interesting thing was the interrupt line, which is typically only drawn to 0Volts if the touchscreen gets touched. After the touchscreen hung up, I measured 0,084V on that line and as long as I touched the screen, this voltage rised to about 0,2V, which for me seems also like a strange behaviour. I also checked the «dmseg» file and got some entries for failed i2c tests of the GoodixGT911. I also tried the github fix for the swapped i2c address, but without success. I used the command «git clone GitHub - pimoroni/hyperpixel4: Driver for the Pimoroni HyperPixel 4.0" Touchscreen Display -b pi4-i2c-fix » for that.
What do I try next?
I dont have any clue what to do next. My only solution in mind, is to undo the «improved» wiring of my 2nd PCB to get as close as possible my first PCB version.
Conclusion :
I really need help and hope, someone can do me this favour. I’ve never found my described error behaviour in any forum. Are there any other usable forums for problems with the Hyperpixel 4.0? Let me please know.
Update:
I tried to reproduce the errors and specify the error source. As above mentioned, the touchdriver hangs up on lightmode (nearly every pixel on rgb(255,255,255)). If i change the color in lightmode to around rgb(245,245,245) the error does not occur. I also noticed that there are two flatband cables on the Hyperpixel 4.0: One for displaying the image and another for the whole I2C-Communication to the touch driver. I plugged out the one for displaying the image and got no problems at all. Even if was theoretically in lightmode(if display would have been on). The touchscreen worked fine and transmitted everyting flawless:
Conclusion on my Update: It seems as the rgb(666) datalines for displaying the image on the screen cause some problems on the I2C bus. I also checked the bus and the power supply with an oscilloscope but I haven't seen any unusual behaviour in any case. Voltage ripple was around 200mV Peak to Peak and the I2C-Datalines rised and fell really sharp
I still need help from you!
Thanks, Manuel

Simulink Raspberry Hardware External Mode Error Issue

I have a problem using Raspbery Pi hardware and Simulink, shown by the pictures below.
I'm tring to control an LED and GPIO pin on the Raspberry Pi.
I click Build, Deploy & Start. It works.
But then I click Monitor & Tune for monitoring signals.
It produces an error which I cannot find a solution for.
I tried different versions of Matlab but got the same error.
My hardware settings are just like in this link: https://www.mathworks.com/help/supportpkg/raspberrypi/examples/communicating-with-raspberry-pi-hardware.html
In addition I tried to click connect on external mode panel and the result is the same, the error is same.
Do you have any suggestions?
[Cross posted from Matlab Answers].
Check your matlab search path. You have the support package 2019a and 2019b on your search path. Add only the one matching your matlab version.

Raspberry pi resetting after reboot

I am trying to over clock my rasbian raspberry pi, but when I change any files beyond /sys/devices/system/cpu and restart, the changes are not saved. I tried echoing to the files and nano and cat. Nothing will work.
SysFS (mounted on /sys) is not a regular filesystem, the elements in this FS represent different aspects and options exposed by the kernel and modules, as such, those parameters are not persisted on secondary memory.
Is normal that changes under that directory are not saved (the only ones I recall to be saved are some settings about power saving in some notebooks, those settings were saved in the BIOS), in order to have the changes on every reboot you should create a init script or modify /etc/rc.local (on Debian based systems as Raspbian).
My SDcard was doing the same thing.
I tried to re-burn the image to the card, but it still had the same problem.
I burnt the image to another SD card, and it worked right away.
More than likely the card was corrupted or damaged

New raspberry pi model a+ trouble

I have just got the new Raspberry Pi model a+ and was very excited. Removed the old model a, and replaced it with the new model a+'s 26 compatible pins. I started fine, and I can see it runs the code as it should. However, I have already run into two problems.
The HDMI port does not show anything on the screen anymore. This has never been an issue before. I use the LINDY hdmi to vga adaptor.
I was very excited to see how much the powerconsumption would decrease. But was very disapointed to see the powerconsumption actually increased by 50%, whitch was a bit of a blow.
I have just replaced the old model a with the new model a+ and copied a raspian image to a 16gb micro sd. I know there is not a lot of experence yet on the subject, but maybe some of you also will have simular problemems?
Best Regards Allan
Try running a
sudo apt-get update
and
sudo apt-get upgrade
on another Pi with the same SD card inserted. There might be some necessary software updates required for the A+.