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BrokenHardware

Introduction

When certain hardware feature break (like buttons for instance), Replicant can remains perfectly usable, however if something goes wrong, it could prevent users from being able to recover their devices or data.

Volume up button

On several devices, the volume up button is used for several things:
  • When the device is powered down, it enables users to go straight in the recovery mode.
  • When the device is powered down, users can use the volume down button to go in download mode. But to do that they also need to use the Volume up button to confirm that.

If the volume up button is broken on a device that uses it for the things mentioned above, then it will be complicated to recover it.

Sometimes it's still possible to do it by disassembling the device and shorting the connector that is used to connect to the button.

Volume down button

On several devices, the volume down button is used to go in download mode.

So without it:
  • You will need to make sure that the recovery image always boots.
  • It's probably a good idea to enable adb and make sure you can get a root shell in the recovery to be able to at least access your data in case of issues.

USB connector

If the USB connector cannot be used to charge anymore, it might still be possible to charge batteries with external chargers. Some phones dock for instance have that feature. We don't know if data works or not when only the charging pins are broken.

If instead the device has no working data this could lead to additional issues as it is needed for several features:
  • Download mode: you may be unable to recover the device anymore
  • You won't be able to use adb
  • You won't be able to easily backup the phone partitions

For devices that don't have a microSD slot, installing Replicant becomes even more complicated.

Galaxy Tab 2 USB cable

If your USB cable is broken it is best to replace it as you won't be able to use adb at all otherwise.

But with an USB OTG adapter and a male<->male USB cable you could at least manage to get heimdall working: Unlike Linux, the bootloader doesn't the USB port to host mode when an OTG adapter is plugged, so you could abuse that to install a Replicant recovery for instance. Still by default, Replicant recoveries will switch the port to host mode when an OTG cable is detected. So you'll probably need to modify the recovery kernel if you want adb.

Battery

Over time, batteries tend to keep less and less charge. So it last less long in hours. When that happens, they also might make the phone reboot or power off when it tires to use too much current at once.

If the phone shuts down at the wrong moment, it could be dangerous for the device:
  • For devices with a modem, the modem asks Replicant to write its data to the EFS partition. If the phone is shut down during a write operation, it could corrupt data. If the modem data are corrupted, it could make your modem unusable forever if you don't have any backup of that data.
  • During boot, I removed the battery of a Nexus S at the wrong moment, and the device doesn't boot anymore.

So try to keep working batteries to avoid issues.

Display

You might be able to install a recovery image without a working display, however enabling adb in Replicant will be too complex for most people without a screen.

Howeve it's still possible to modify boot.img and recovery images to add a root shell inside it.

It might also be interesting to find out if it's possible to use some assistive technology (like text to speech) to operate a phone without a working display.

Updated by Denis 'GNUtoo' Carikli 3 months ago ยท 5 revisions