The use of Unix in embedded computer systems such as networking equipment, mobile phones, media players, set-top boxes, etc.

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Linux embedded PC fault rectification [on hold]

How to take image of an embedded PC using telnet and how to re-image an Embedded PC using RS232 serial connection.
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45 views

Login automatically as root

I am working with a board and when it finishes the boot, appears the login. What I want to do is login as root but automatically. I mean I want to do that when boot is finish, I can see the prompt, ...
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19 views

Run startx & automatically embedded syste,

I am working with a board in which I run my application which use th graphical mode. Everything works perfect. I start the graphical mode like this: startx & and then I run my application like ...
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0answers
27 views

How to setup ssh over USB on an embedded linux device?

I have an embedded linux device with an ARM processor. I am connecting to it over a USB port using minicom. What should I do to "ssh" into the device through the USB connection? I want to setup ...
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2answers
22 views

Debian system with encrypted data that can be decrypted only from a remote server

This question is about the design of a service I want to setup. Description My purpose is to provide a client box which connects to a server and provides some features. The client box is a small ...
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1answer
40 views

How to download original ramdisk file to the computer? [closed]

Linux embedded, is it possible to download original ramdisk file to the computer, to get source code? Access via SFTP. U-boot 1.2.0 Kernel command line: root=/dev/mtdblock3 ...
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2answers
70 views

How to remount as read-write a specific mount of device?

How to remount as read-write a specific mount of device? (one folder) The file is "Read-only file system", rw-r-r, so it not allow to change permissions. I need to replace that file, then change ...
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3answers
62 views

Unable to delete files as a root user using RS232 serial cross cable

I have a device(CCTV decoder) which was rebooting itself, so cant login using LAN cable. It has RS232 port only, no VGA and keybord/USB port(Embeded PC). I connected RS232 cross cable and used ...
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How to boot on a ramdisk?

I'm working on a linux embedded for a custom board with a ARM9 processor. My kernel version is : 2.6.33 I'm trying to boot on a ramdisk, kernel correctly mount the file system but failed to execute ...
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1answer
82 views

Canot remove symlinks: after reboot, symlinks re-appear

Using ssh from BusyBox, I cannot remove symlinks: after rebooting the device, symlinks re-appear. ls -la shows that symlinks have been removed, but after rebooting device they re-appear again. Those ...
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22 views

Can't access GPIOs when switching to systemd, but why?

I'm using this ARM AT91 Sam9x5ek Embedded Device, with my Linux Images made by a Buildroot. Usually my init-system is Busybox, now I changed it to systemd. Since then I can't access the GPIO anymore, ...
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43 views

How to debug random reboots, with no kernel panic, of an embedded system?

I have two aValue RPC-10W1 embedded systems that reboots by themselves after 1-2 hours. Facts: The board will reboot within a time span of 1 to 2½ hours. The issue is present on two identical ...
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1answer
61 views

How to connect to ssh-server running on embedded linux without /etc/passwd?

After installing ssh server on my remote machine (which runs embedded Linux), I tried to connect to ssh server from host machine but it failed. This is because I could not specify user account when ...
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1answer
47 views

How to check my account on embedded linux without “/etc/passwd”?

On some embedded linux systems, there is no /etc/passwd file and /etc directory is not writable (which means I cannot set user account and password?). Then what is my (default) account name and ...
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1answer
55 views

How to know free disk size witout df command? [closed]

Is it possible to check free disk size in Linux without using command lines such as df? Since my host machine is embedded Linux, there are no direct command lines that show free disk size.
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2answers
58 views

Secure the content of a hard disk

I have to prepare a computer to give away, and I do not know who is going to use it. The computer has Debian installed, and the HDD is entirely encrypted. All users have their storage on the server. I ...
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52 views

Why is my swap not being activated automatically via fstab?

I've got a Linux embedded system that I'm experimenting with (the Elektor Embedded Linux Made Easy board, based on the GNUBLIN http://en.gnublin.org/index.php/GNUBLIN-Elektor). I'm using the 3.3 ...
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1answer
23 views

Late running of scripts during bootup, ending with a reboot without the login prompt

I'm making a special "installer" for an embedded system where I'd like the kernel to boot up, execute a set of things very late in the process where the peripherals have been set up and then reboot ...
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38 views

redirecting output of /dev/fb0 to /dev/fb2

I am using IMX6 Saberauto board on Linux OS. I have 2 displays primary is HDMI and secondary is LVDS. I want to run 2 applications. One QT on primary display, which I am able to do. Second ...
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92 views

Can't login using serial on ttyO0 - BeagleBone Black

I boot Beaglebone Black, connected to my desktop by serial. It was working great, until now. Beagle is booting, output shows up on the console, but at the end I can't log in. I can't type the login, ...
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0answers
40 views

How do I know from a BeagleBone Black if it is connected via USB (as a client/slave)?

BeagleBone Black has an USB port which allows the user to access it through ssh. In general, we could say that when you plug it to a PC, the PC is the USB host and the BBB is the USB client. On the ...
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1answer
53 views

What are the disadvantages of uClibc?

I try to speed up my boot sequence, and somebody recommends to use the uClibc instead of Glibc. I've built an image with it, it gets smaller and faster to boot — but at which cost? Does anyone know ...
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46 views

cross compile embedded arm

I have the android 4.2.2 code in directory /home/sghPhone2 which compiles normal with make menuconfig but I need to compile a 4.4 kernel and possibly patch it but when I download the source from ...
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2answers
108 views

tftpput in U-Boot: error: 'Access violation' (2)

I have enabled CONFIG_CMD_TFTPPUT in U-Boot, but I am not able to use it. I have set the serverip and ipaddr environment variables. When I use it as follows, it times out: u-boot# tftpput ...
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Is there a limit of GPIOs that can be used in Linux?

When it comes to use GPIOs, is there a limited number that can be used in Linux (except through the limitation of the physical availability/amount of the ports/pins) or is it theoretically possible to ...
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90 views

Unable to add serialport (nodejs module) when generating filesystem and cross-compiling tools for an ARM processor

I am using buildroot (version 2013.08.1) to generate the filesystem and cross compiling tools to implement embedded linux on a i.MX233 processor (ARM architecture). I add the serialport module by ...
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36 views

What are the two head.S files in linux source ?

In the linux source there are two different head.S files located at: arch/arm/kernel/head.S arch/arm/boot/compressed/head.S What is the puprpose of each one and what is the order of there execution ...
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9 views

WAN interface using his own queues for QoS different that the provided by Linux

My Linux embedded system have a WAN interface with the default pfifo_fast qdisc attached to it. The web interface for configuring the system let the user configure three Queues for the WAN interface ...
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1answer
100 views

Why isn't sda1 showing up in dev and how can I fix that?

I have an embedded Linux device and I was trying to copy some files to it. I plugged in a USB stick, the dmesg shows that it was recognized, but for some reason /dev/sda1 never showed up. I'm trying ...
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1answer
30 views

How do you ensure physical network interfaces always get the same interface name across reboots on an embedded Linux system?

For an embedded Linux system, if I have two or more network interfaces, how do I ensure that they always get the same interface names every boot In other words, I want, for example, eth0 to always ...
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3answers
92 views

What are the minimum root filesystem applications that are required to fully boot linux?

It's a question about user space applications, but hear me out! 3 'applications', so to speak, are required to boot a funcitonal distro of Linux: Bootloader - For embedded typically that's U-Boot, ...
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2answers
112 views

Kernel does not skip bad blocks when mounting filesystem

I am developing for an embedded Linux application using friendlyARM's micro2440. It runs on a Samsung s3c2440 ARM processor and uses squashfs in its NAND flash. Recently, some flash blocks went bad. ...
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1answer
128 views

How configurable is MPTCP?

I work on embedded Linux devices that usually have hard wired Ethernet as well as cell modem connections. If I were to use MPTCP would it be possible to easily configure the system to use eth0 all ...
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2answers
67 views

live dd over a mounted read-only root partiton

I'm trying to conceive a firmware update mechanism for a Linux-based embedded system without an additional initrd/initramfs/whatever. From within the running system which has a read-only mounted root ...
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34 views

Get log from kernel while loading

There is a arm/omap2-based device without ethernet, UART ports. It has usb connection with host, numeric keyaboard, LCD display. There is working U-Boot and kernel images for this. I'm trying to ...
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Interfacing with a custom camera in Linux on the beaglebone

I'm new to Linux development and need some pointers to help me get a camera (OV7670) working on a beaglebone running Debian. Using the camera capes as a guide, I've connected the camera to the GPMC ...
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30 views

Use Rsync with HTTP

Is it possible to use rsync with an HTML POST request? If so what would the rsync command look like? For example let's say using HTML5 I have this (bear with me going back to linux stuff): <form ...
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3answers
81 views

Can I achieve functionality similar to interrupts in Linux userspace?

One of functionalities I miss the most from "small embedded" in Embedded Linux is the interrupts. A signal appears on a specific pin, or other interrupt source is triggered and whatever was done ...
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4answers
180 views

Corruption-proof SD card filesystem for embedded Linux?

Recently we had a rather unpleasant situation with our customer - Raspberry Pi based "kiosk" used to display remote sensing data (nothing more fancy than a kiosk mode browser displaying a ...
3
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1answer
452 views

Which TCP congestion control algorithm is best for low speed radio modems?

On my project we have remote Linux nodes that communicate over the Internet via very low speed CDMA cell modems. The bandwidth on these modems is about 2kbyte/second and the RTT back to the server is ...
3
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1answer
96 views

Why doesn't 'ar' work like the manpage says?

I'm trying to use 'ar' included in Debian Wheezy armel version of binutils and it doesn't seem to operate like on other systems I've encountered. Some sample output from the command-line: $ ar ...
3
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1answer
132 views

Booting using initramfs instead of uramdisk

I am working on Zynq Microzed board. It is booting perfectly with uramdisk.image.gz but I trying to boot it with initramfs.cpio. In this regard I have made following changes in header files of ...
2
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1answer
103 views

Most reliable way to check for connected client?

I have an embedded Linux OS developed from scratch using Yocto. This talks to a Windows XP/7 client. The embedded OS runs a DHCP server and gives an address to the client. The problem is that the ...
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0answers
54 views

How can I make a configuration web page for a linux appliances? Any pre made solutions available?

I am putting together a bunch of embeded linux appliances that we will be installing at a few locations. Built the whole thing from scratch using Raspbian (debian based) and Raspberry Pis. There are ...
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0answers
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Removed USB storage device is still mounted

I'm working on a embedded linux system based on busybox. Sometimes a USB device which is physically removed from the post is still displayed in mount, df or /proc/mounts. If I reattach the device, it ...
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1answer
68 views

How to get log from u-boot without com-port

U-boot is configured to print its logs into com-port by default. There is a device I can't receive this information (without uart/com). Can I configure u-boot to store its log strings into some place ...
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1answer
131 views

Conntrack TCP Timeout for state stablished not working

Im using a private IP address and I want to keep alive SNAT entries in my Router (Gateway) for at least two hours (some windows apps of my network are using TCP keepalive set to 2 hours). Gateway is a ...
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0answers
107 views

using sf probe to make u-boot faster

My uboot was running slow on a ARM cortex A9 processor based Xilinx zynq chip. Xilinx forum referred me to the following to solve this issue: +From 0a212cfc2dd4e4d1595de2ca2dde3f642e5707e7 Mon ...
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1answer
121 views

How can I boot with a compressed rootfs?

My problem is: I cannot use compressed rootfs (the kernel crashes during boot) but uncompressed ones work fine. What I did: I'm using Buildroot 2013.11 to generate Images for my embedded Linux ...
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2answers
81 views

Could not mount UBIFS on SD card

I guess this is not a big problem, still I can't see what's the matter. I'm building Images for an Embedded Linux (2.6.39) ARM9 System with Buildroot 2013.11, which is booting from an SD card. I was ...