Troubleshooting Reinstall
Contents
MOD does not boot, or boots into recovery mode automatically
If the main MOD OS kernel becomes unbootable, the MOD will automatically boot into restore mode (used for performing OS updates).
You know the MOD is in restore mode if the inputs and output leds are blue and the display says "plugin USB cable to PC" or "copy file, eject and unplug".
When this happens we need to force a new installation of the MOD OS.
We do this by starting the restore mode with a special "force install" flag.
The method for starting this special mode is:
- Turn off your MOD
- Hold the left knob and footswitch down (on the Duo X use the 1st button from the bottom-left)
- Turn on the MOD (while still holding the knob and footswitch down)
- Wait 5 seconds and let go of the knob and footswitch - the MOD is now booting into restore mode
- Connect the MOD to your PC (if not done yet) and wait for a new mass storage drive to appear
- Download the latest release from Releases
- Copy the mod*.tar file you just downloaded onto the new drive and use your OS option to safely remove the drive
- Disconnect the USB cable
Note: On some rare cases a MOD Duo might boot again in restore mode after this. If that happens please start over from step 1.
MOD does not boot at all, not even in restore mode
If for some reason your MOD device does not boot at all - not even in forced-restore mode - we need to reinstall the bootloader or perhaps the entire OS inside.
If you have a MOD Duo X unit that cannot boot normally or in forced-restore mode, please contact support@moddevices.com.
This part of the troubleshooting section does not apply to the MOD Duo X, as it does not have a FEL button and thus cannot be forced to boot custom payloads.
Please note that there are 2 different kinds of MOD Duo units - older ones with nand flash and newer ones with eMMC.
The new unit models have their name (like "MOD Duo") written and engraved above the right display.
Knowing which type of unit you have is important as the reinstallation/reset procedure is not the same for each one.
(MOD Duo X units are always of the newer eMMC type)
For older Duo models:
You can first try to reinstall the bootloader, which will keep all data intact, but if the issue is somewhere else the MOD will continue to not boot.
This is the best option, if it works. (and applies to your unit, of course)
If that does not work, you can perform a factory reset, which will erase all your data.
For all Duo models:
You can reinstalling the OS over USB, optionally formatting/reset the user data partition as well.
This method only works on Linux at the moment.
Reinstall bootloader
NOTE: Only for older MOD Duo units with nand flash
Requirements: Linux or macOS, basic command-line knowledge
To begin:
- Click and hold down the FEL button on the back of the MOD Duo (in tiny hole), while you power it on.
- Hold it for 2 seconds, then release
- Connect the MOD Duo to your computer via USB cable
- Download https://github.com/moddevices/CT_NandBoot/archive/master.zip and extract it
- Open a terminal and 'cd' to the directory where master.zip was extracted, ie:
cd ~/Downloads/CT_NandBoot-master/
If you're running macOS, run:
./bootfix.osx
If you're running Linux 64bit, run:
./bootfix
(sudo will likely be needed here)
For non-64bit Linux systems, run 'make clean' and 'make' beforehand.
After the command finishes running, just power the MOD off and on again.
If it still doesn't boot after 2 minutes, a factory reset or OS reinstall via USB is needed.
MOD Duo Factory Reset
NOTE: Only for older MOD Duo units with nand flash
Requirements: Linux or macOS, basic command-line knowledge
For a factory reset under Windows, see Troubleshooting_Reinstall_via_LiveSuit. (applies only to older MOD Duo units with nand flash)
To begin:
- Click and hold down the FEL button on the back of the MOD Duo (in tiny hole), while you power it on.
- Hold it for 2 seconds, then release
- Connect the MOD Duo to your computer via USB cable
- Download this file: http://download.moddevices.com/releases/modduo/reset/modduo-latest-reset-image.raw
- Download https://github.com/moddevices/CT_NandBoot/archive/master.zip and extract it
- Open a terminal and 'cd' to the directory where master.zip was extracted, ie:
cd ~/Downloads/CT_NandBoot-master/
If you're running macOS, run:
./bootfix.osx -w ~/Downloads/modduo-latest-reset-image.raw
(adjust the path to 'modduo-latest-reset-image.raw' as needed)
If you're running Linux 64bit, run:
./bootfix -w ~/Downloads/modduo-latest-reset-image.raw
(adjust the path to 'modduo-latest-reset-image.raw' as needed, sudo will likely be needed here)
For non-64bit Linux systems, run 'make clean' and 'make' beforehand.
Continuing:
- Wait until the 'bootfix' process finishes
- Power off and on the MOD Duo (by replugging the power cable)
- Wait until its LEDs turn blue, after around 30 seconds. If the LEDs don't light up after one minute, replug the power cable once again
- Wait until the LEDs turn red, then green. This should take around 10 minutes.
Once the LEDs are green, the MOD Duo has finished its factory reset.
Power it off and on again one last time, and it will be good as new :)
If the LEDs are still blue for too long (actually they go to red and then return to blue) or the display shows the message "copy file, eject and unplug", please execute all this process again starting from the bootfix command.
Reinstall via USB boot
Requirements: Linux, basic command-line usage
To begin:
- Click and hold down the FEL button on the back of the MOD Duo (in tiny hole), while you power it on.
- Hold it for 2 seconds, then release
- Connect the MOD Duo to your computer via USB cable
- Download http://download.moddevices.com/releases/modduo/tools/mod-boot-fel-restore-v2.tar.gz and extract it
- Open a terminal and 'cd' to the directory where mod-boot-fel-restore.zip was extracted, ie:
cd ~/Downloads/mod-boot-fel-restore/
If not you're running 64bit, install sunxi-tools from your Linux distribution, and copy /usr/bin/sunxi-fel to the current directory, overriding the existing file there.
Continuing, we will run a command with different environment variables depending on the target unit.
For the MOD Duo 2020 unit, run:
EMMC=1 ./boot-fel-restore.sh
For non-kickstarter units, run:
MARS=1 ./boot-fel-restore.sh
For kickstarter units, run:
./boot-fel-restore.sh
(NOTE: it might be possible that kickstarter units have the "MARS" model, and a non-kickstarter one not. It is not possible to tell just by looking at the unit externally, so if the command with "MARS" does not work for you, try the one without, and vice-versa.)
- After the script finishes, wait for around 2 minutes, and the MOD Duo will boot into recovery mode.
- Install a MOD OS release as usual.
Note: You can find all MOD OS software releases in the Releases section.
