[MeMO Pad 7 Original Android Development] lambdadroid:
/*
* Your warranty is now void.
*
* I am not responsible for bricked devices, dead SD cards,
* thermonuclear war, or you getting fired because the alarm app failed. Please
* do some research if you have any concerns about features included in this ROM
* before flashing it! YOU are choosing to make these modifications, and if
* you point the finger at me for messing up your device, I will laugh at you.
*
*/

me176c-boot is a custom, unlocked bootloader for the ASUS MeMO Pad 7 (ME176C(X)). Designed to be simple and flexible, it can boot into Android and/or Linux.

me176c-boot is a combination of systemd-boot (a simple UEFI boot manager) and android-efi (a simple Android bootloader).

Features

Boot into Android, Recovery and Fastboot

Unlocked bootloader, can boot into custom ROMs

Completely open-source and custom built for ASUS MeMO Pad (ME176C(X))

Flexible configuration to add further boot targets (e.g. Linux dual boot)

Download

Latest release: esp-0.3.0.zip

Older releases: Available on GitHub

Installation

Make sure that you are running Android 5.0 (Lollipop).

Download and unpack "esp.zip" from the latest release.

Make sure you have Fastboot installed.

Boot the tablet into Fastboot mode: On the stock ROM, press "Volume Down" + "Power", and release the "Power" button once the backlight turns on.

Connect the tablet to your PC, and verify that it shows up in "fastboot devices".

Flash the new EFI System Partition (ESP) extracted from the downloaded ZIP: "fastboot flash ESP esp.img"

Recommended: Configure the bootloader to use the stock charger for offline mode charging

Usage

By default, the bootloader will boot into the main Android system. You can recognize the bootloader by the green Android robot that is shown on boot.

Press "Volume Down" while booting to show the boot menu. Navigate through the menu with the "Volume Down" key. Press "Volume Up" to select an option. The "Power" button is not working inside the boot menu.

Configuration

You can access the (systemd-boot) configuration files from Recovery: go to "Mount" and select "EFI System Partiton (ESP)". Then you can access the ESP using ADB at "/esp".

Here are some links with more information how to configure the bootloader:

"systemd-boot" on ArchLinux Wiki

android-efi README ("android" boot type is supported in me176c-boot)

Booting from other partitions

There is an additional "volume" option in me176c-boot that allows booting from other partitions on the internal storage, based on their GPT partition UUID. The partition needs to be formatted as FAT32.

Examples

Using the stock charger (recommended)

Booting into main OS on charger insertion

Dual/multi boot (e.g. Android and Linux)

Limitations

The "BIOS" of the tablet can boot from the internal storage and USB(-OTG). It does not seem to be able to boot directly from external SD cards. However, it is possible to keep most of the system on the external SD card by placing only the kernel (the boot partition) on the internal storage.

The EFI System Partition (ESP) is severely limited in its size (only 16 MiB), which is usually not enough to keep more than one Linux kernel. That’s why me176c-boot supports booting from other partitions on the internal storage.

Setting up an additional ESP partition

There is an unneeded APD (ASUS Product Demo) partition on the tablet, which has a reasonable amount of storage (~300 MiB) and is therefore ideal as additional ESP partition. It contains a few demo product images/media files that are only used for the "demo mode" on the stock ROM.

Boot into TWRP recovery and make a backup of the "APD (ASUS Product Demo)" partition. Store in it a safe place in case you want to restore it.

Wipe the APD partition, and change its file system to FAT32.

Place the EFI application (e.g. Linux) on the APD partition, and use it in a boot target using the "volume" option:

# Partition UUID of the APD partition
volume 80868086-8086-8086-8086-000000000007

Troubleshooting

In some cases booting may fail or you make a mistake during the installation. In this case, first power off the tablet by holding the "Power" button until it turns off.

Recovery

Even with the bootloader entirely broken, you can still boot into Fastboot mode using the rescue mode ("DNX mode").

Download the stock ROM ("UL-K013-WW-12.10.1.36-user.zip")

Extract "esp.zip" and "droidboot.img" from the downloaded ZIP.

Extract "EFI/Intel/efilinux.efi" from "esp.zip".

Press "Volume Up" + "Volume Down" + "Power" until "Fastboot starting…" shows up on the display.

Connect the tablet to your PC, and verify that it shows up in "fastboot devices".

fastboot flash osloader efilinux.efi
fastboot boot droidboot.img

XDA:DevDB Information

me176c-boot - Custom, unlocked bootloader for ASUS MeMO Pad 7 (ME176C(X)), Tool/Utility for the Asus MeMO Pad 7

Contributors

lambdadroid

Source Code: https://github.com/me176c-dev/me176c-boot

Version Information

Status: Stable

Created 2018-04-20

Last Updated 2019-07-19