update FAQ

en/faq.md

@@ -1,8 +1,40 @@
 # OpenIPC Wiki
 [Table of Content](../index.md)
 
-Questions and answers
-----------------
+Frequesntly Asked Questions
+---------------------------
+
+### How to get into bootloader shell?
+
+If you can't interrupt the boot sequence with a key combination, or if your
+camera requires a bootloader password that you don't know, you can still make
+it stop the Linux kernel booting and throw you into the shell.
+
+Short-circuit pins 5 and 6 of the flash chip with a small metal object,
+a screwdriver or tweezers, right after the bootloader starts but before it
+calls up the Linux kernel.
+
+Pins 5 and 6 of the SOIC8 chip are on the opposite corner of pin 1, indicated
+by the embossed or drawn dot next to it.
+
+![](../images/flash-pins.webp)
+![](../images/flash-pins-2.webp)
+
+### How to reset camera settings from U-Boot
+
+Sometimes improper settings make the camera unstable to the point where it is
+impossible to log in or not enough time before rebooting to fix the settings.
+Here's how to completely erase the overlay partition in the OpenIPC firmware,
+right from the bootloader shell, to bring the camera back to its pristine state:
+
+__only for 8MB flash partitioning__
+```
+sf probe 0; sf erase 0x750000 0xb0000; reset
+```
+__only for 16MB flash partitioning__
+```
+sf probe 0; sf erase 0xd50000 0x2b0000; reset
+```
 
 ### How to sign in into camera via SSH?
 
@@ -12,13 +44,17 @@ There is no password by default.
 
 ### How to sign in into camera Web UI?
 
-Open http://<camera_ip_address>:85/ and sign in using default username _admin_ and default password _12345_.
-You will be asked to change the password after successful login. __Please note, it will also change your ssh root password!__
+Open http://<camera_ip_address>:85/ and sign in using default username _admin_
+and default password _12345_. You will be asked to change the password after
+successful login.
+
+__Please note, it will also change your ssh root password!__
 
 ### How to reset password for SSH/Web UI?
 
-Create a serial connection to the camera using a UART adapter and a terminal program.
-After turning on the camera, press Ctrl-C to interrupt the boot sequence and enter the bootloader shell.
+Create a serial connection to the camera using a UART adapter and a terminal
+program. After turning on the camera, press Ctrl-C to interrupt the boot
+sequence and enter the bootloader shell.
 
 For a camera with 8MB flash chip, run
 ```
@@ -35,14 +71,24 @@ Sign in on camera via `ssh` and run `ipctool`.
 
 ### I don't see ipctool on camera. Why?
 
-You don't see it because initially it is not there, but there is a shell command of the same name. _(Since it's a shell command, it won't work from Web Console in web UI. Sign in to the camera via SSH and run the command in there.)_ When you run this command, the latest available version of `ipctool` utility gets downloaded into `/tmp/` directory and runs from there. Since the utility resides in `/tmp/`, it won't survive a reboot, thus won't take any useful space on the camera afterwards.
+You don't see it because initially it is not there, but there is a shell
+command of the same name.
 
-If you need to know what's in the command, search for `ipctool` in `/etc/profile` file.
+_(Since it's a shell command, it won't work from Web Console in web UI.
+Sign in to the camera via SSH and run the command in there.)_
+
+When you run this command, the latest available version of `ipctool` utility
+gets downloaded into `/tmp/` directory and runs from there. Since the utility
+resides in `/tmp/`, it won't survive a reboot, thus won't take any useful space
+on the camera afterwards.
+
+If you need to know what is in the command, search for `ipctool` in the
+`/etc/profile` file.
 
 ### How to dump full firmware to an NFS share
 
-This could work if you are lucky, you gained access into Linux shell
-on stock firmware, and it does support NFS mounting:
+This could work if you are lucky, you gained access into Linux shell on stock
+firmware, and it does support NFS mounting:
 ```
 fw=$(mktemp -t)
 nfs=$(dirname $fw)/nfs
@@ -53,8 +99,6 @@ mv $fw ${nfs}/firmware_full.bin
 ```
 Make sure to use your own IP address and path to the NFS share!
 
-
-
 ### How to find original MAC address in a firmware dump
 
 ```
@@ -68,71 +112,99 @@ __On the camera__: Sign in into web UI on port 85 of your camera.
 passwd
 ```
 
-__On the desktop__: Copy the public key to the camera by logging in with the password created above.
+__On the desktop__: Copy the public key to the camera by logging in with the
+password created above.
 ```
 ssh-copy-id root@192.168.1.666
 ```
 
-__On the camera__: Create a `.ssh` folder in the root user's home directory and copy the file with the authorized keystore into it.
+__On the camera__: Create a `.ssh` folder in the root user's home directory
+and copy the file with the authorized keystore into it.
 ```
 mkdir ~/.ssh
 cp /etc/dropbear/authorized_keys ~/.ssh/
 ```
 
-__On the desktop__: Open a new session to verify that the authorization is passed using the public key not requesting a password.
+__On the desktop__: Open a new session to verify that the authorization is
+passed using the public key not requesting a password.
 ```
 ssh root@192.168.1.666
 ```
 
+
 ### Majestic
 
 #### How to get a memory dump for debugging?
+
 Enable and configure Core Dump in the menu Majestic > Majestic Debugging.
 
 #### Camera image has a pink tint
-You need to specify the GPIO pins to control the infrared filter.
-The settings for some cameras can be found in the [table](https://openipc.org/wiki/en/gpio-settings.html).
-If your camera is not in the table, then you will need the [ipctool](https://github.com/OpenIPC/ipctool/releases/download/latest/ipctool) utility.
 
-The OpenIPC firmware will automatically download the latest version of the utility to the /tmp directory when `ipctool` is invoked first time.
-On native firmware, you will need to download the utility to the camera yourself using the tools available in the system: wget, curl, tftp...
-For example, download the ipctool utility to TFTP server on the local network, then download it to the camera:
+You need to specify GPIO pins to control the infrared filter.
+Settings for some cameras can be found in [this table][1].
+If your camera is not in the table then you need to use [ipctool utility][2].
+
+The OpenIPC firmware will automatically download the latest version of the
+utility to the /tmp directory when `ipctool` is invoked first time.
+
+On stock firmware, you will need to download the utility to the camera yourself
+using any tools available in the system: wget, curl, tftp etc.
+
+For example, download the ipctool utility to TFTP server on the local network,
+then download it to the camera:
 ```
 tftp -g -r ipctool -l /tmp/ipctool 192.168.1.1
 chmod +x /tmp/ipctool
 /tmp/ipctool
 
 ```
-If the camera has internet access, you can try to mount a public NFS sharing and run the utility from it, without downloading to the camera:
+
+If the camera has access to the internet, you can try to mount a public NFS
+sharing and run the utility from it, without downloading to the camera:
 ```
 mkdir -p /tmp/utils
 mount -o nolock 95.217.179.189:/srv/ro /tmp/utils/
 /tmp/utils/ipctool
 ```
 
-After the utility is downloaded to the camera, run the `ipctool gpio scan` command in the terminal and open-close the camera lens a couple of times with your palm.
-Watch the output of ipctool to determine the pins responsible for controlling the IR filter curtain.
-Enter the values obtained in the settings for the night mode Majestic. If the pink tint still persists, you may need to enable sensor signal inversion.
+After the utility is downloaded to the camera, run the `ipctool gpio scan`
+command in the terminal and open-close the camera lens a couple of times with
+your palm.
+
+Watch the output of ipctool to determine the pins responsible for controlling
+the IR filter curtain.
+
+Enter the values obtained in the settings for the night mode Majestic. If the
+pink tint still persists, you may need to enable sensor signal inversion.
 
 Don't forget to add the camera model and found GPIO values to the table!
 
-#### Is it possible to display the data for setting the auto focus of lenses instead of the current sample_af in the standard /metrics?
+#### Is it possible to display the data for setting the auto focus of lenses
+instead of the current sample_af in the standard /metrics?
+
 No, this is a difficult algorithm, it does not have a sense to run it this way.
 
 #### Copy files from Linux system to camera
-Sometimes you need to transfer files to the camera. In addition to the above method using NFS (Network File System)
-you can use the standard Linux scp command to copy files over an SSH connection:
+
+Sometimes you need to transfer files to the camera. In addition to the above
+method using NFS (Network File System) you can use the standard Linux `scp`
+command to copy files over an SSH connection:
 ```
 scp ~/myfile root@192.168.1.65:/tmp/
 ```
-This command will copy myfile from the home directory to the /tmp directory on the camera.
+This command will copy `myfile` from the home directory to the `/tmp/`
+directory on the camera.
+
 On recent Linux systems the following error may occur:
 ```
 sh: /usr/libexec/sftp-server: not found
 scp: Connection closed
 ```
-
-Add -O option in this case:
+In this case, add `-O` option to the command:
 ```
 scp -O ~/myfile root@192.168.1.65:/tmp/
 ```
+
+
+[1]: https://openipc.org/wiki/en/gpio-settings.html
+[2]: https://github.com/OpenIPC/ipctool/releases/download/latest/ipctool