[Unofficial] Fixing a hardbricked Yuphoria (lettuce) using an external SD card

Requirements:

• A hardbricked Yuphoria/lettuce (YU5010/YU5010A) - when connected with a PC, it should expose itself as QHUSB_BULK (when no driver is installed)/Qualcomm HS-USB QDLoader 9008 (when appropriate driver is installed).
• (Optional) A working Yuphoria/lettuce, if you want to create the recovery image yourself.
• A microSD card - contrary to the popular belief, you don't need a 16 GB or bigger one. 1 GB is sufficient.
• Win32 Disk Imager (Windows) / dd (*nix).

Information regarding the recovery image:

The partition structure of Yuphoria is as follows:

From the above table, its evident that dumping the first 200 MB should be enough to include all required partitions, but you can opt for a full dump as well.

To dump, we can use any of the following methods:

• Directly to the PC using ADB.
• Be rooted, connect to adb shell with root privilege & call dd to dump it in external sdcard.
• Without being rooted but on unlocked bootloader, boot to (tethered booted/permanently flashed) TWRP, get shell access in TWRP or via adb shell, call dd to dump it in external sdcard.

For dumping the whole eMMC, use:

Code:

dd if=/dev/block/mmcblk0 of=/external_sd/backup.img bs=512 count=30535646

For dumping first 200 MB, use:

Code:

dd if=/dev/block/mmcblk0 of=/external_sd/backup.img bs=1M count=200

You can directly write to the external sdcard as well:

Code:

dd if=/dev/block/mmcblk0 of=of=/dev/block/mmcblk1 bs=1M count=200

Be very careful working with dd! mmcblk0 is the eMMC and mmcblk1 is the external SD card.

Pre-created eMMC dump:

https://drive.google.com/folderview?id=0B9zZIJPXbMsuaGg2SXFHcW5mbzQ&usp=sharing

• It is created from a bootloader unlocked Yuphoria running cm-12.1-YOG4PAS47N build.
• The size of the whole dump is ~14.5 GB.
• After compression, the size is ~998 MB. Its compressed using 7-Zip & split into 10 parts.
• File hashes (SHA-1) are as follows:

Usage:

1. Download the eMMC dump created by me or make it yourself.
2. Use Win32 Disk Imager (Windows) / dd (*nix) to write in a microSD card. I've used a 16 GB Class 10 one.
3. Insert the sdcard into the hardbricked Yuphoria, insert the battery, press Volume Up key & connect it with PC. It should expose itself as a bootloader/fastboot interface.
4. Flash official Cyanogen OS - you may need to omit the bootloader unlock/re-lock part.
5. Profit!

Note:

• Try at your own risk! If you've any doubt, please contact with the nearest YU service center & ask them for a replacement.
• Credit goes to the countless number of people, who risked their devices to find a working method to unbrick it (especially the girlfriend of my friend, who was forced to lend her device for the experiment).
• The process is known to many persons out there - earlier I advised some of the Yureka users to try it out, but didn't get any further feedback. Credit goes to @Ricks for testing the hypothesis on Yureka on his own.
• Please provide detailed feedback regarding your success/failure story, so that this tutorial can be enhanced more.