[Xperia Z1 Original Android Development] abbychauhan:
"Post Updated on 22/06/2014"

MultiBoot Totally Simplified (Noob Friendly)

Whole Multiboot Procedure for better understanding..

We will do this in two parts procedure as Follows -

Part 1 -

First we will do the mainrom creation. "Mainrom" - The ROM which is Currently installed on your phone.

1. First Download bootmenu_honami.rar, extract folder "bootmenu" to your Phone's Internal storage

2. Put boot.img or kernel.elf (Of the ROM which is Currently installed on your phone) to the mainrom folder (its in the bootmenu folder) of extracted rar file,

make sure thats the same kernel i.e, boot.img or kernel.elf like your primary rom of yours which is currently installed

boot.img - you can extract it from the ROM zip file or Custom Kernel zip file eg. ROM.zip or Doomloards Kernel zip

Kernel.elf - U ll have to convert kernel.sin from ROM zip file to kernel.elf via Flashtool (It has got option to do that)

3. Download bootmenu.img from attachment, flash bootmenu.img using fastboot commend: fastboot flash boot bootmenu.img

4. Reboot into bootmenu, choose "patch...", navigate to mainrom folder (it has to be in the internal memory, inside the folder bootmenu),

select mainrom.zip package (make sure boot.img or kernel.elf is the same like your current main rom kernel, and make sure boot.img or kernel.elf is in folder "mainrom" ),

select mainrom.zip and click "yes". Main rom will be added into boot menu entry.

Now reboot again into boot menu and you will see new Entry Mainrom and Mainrom - CWM, choose Mainrom from Multiboot Menu to boot into your primary rom or Choose mainrom - CWM to go into mainrom Recovery

Part 2 -

Other ROMs creation - You can do it only if you completed main rom step)

1. Reboot into bootmenu, chose "patch...",

2. Navigate to Second ROM ZIP file

(Keep it anywhere in External Memory Card Because you wont be able to access Internal Memory of your Phone via another ROM Recovery due to change of Partitions, All ROMs will be installed on Internal Memory),

Choose ROM zip you want to patch, patch them

3. Reboot again into boot menu (new ROM entry will be displayed), go into ROM - CWM to go into Recovery of the particular ROM,

Now you are in Recovery of New ROM, Go to install ZIP (Installation of ROM) and

navigate to the same folder where you kept the ROM ZIP file (on External Card Memory),

you will find a new zip with appended name "patched.zip",

chose these patched zip to install trough the Recovery,

4. Flash C6902 fix, if u have C6902 Device (keep it On External Memory too),

5. Boot into ROM then Do a REBOOT and again go to Secondary ROM - CWM

6. Flash Gapps (keep it On External Memory too)

7. Flash Any Mod or anything if you wanted to flash for Your ROM (keep it On External Memory too)

Except Custom Kernels or Something that will wipe bootmenu.img ( Its WIP you can check out the Conversations on Page 48/49/50 )

8. Do Reboot

9. In Bootmenu Select the Newly installed ROM.

You are done!

Enjoy!

Common Questions -

1. How many ROMs I can Install?

Answ - http://xdaforums.com/showpost.php?p=53236187&postcount=399

2. How to go from One ROM Partation to Another ROM Partation via File Explorer?

Answ - http://xdaforums.com/showpost.php?p=53318812&postcount=476

3. How to get kernel.elf?

Answ - http://xdaforums.com/showpost.php?p=53234909&postcount=384

and http://xdaforums.com/showpost.php?p=53234988&postcount=386

and http://xdaforums.com/showpost.php?p=53235075&postcount=387

4. How to take Screenshot of CWM?

Answ - http://xdaforums.com/showpost.php?p=53229901&postcount=358

and http://xdaforums.com/showpost.php?p=53230193&postcount=362

5. We get ROM updates now and then how do we do it? If we want to remove The Whole Multiboot Thing or a ROM from Bootmenu and to uninstall it completely from our phone then what is the procedure?

Answ - http://xdaforums.com/showpost.php?p=53076327&postcount=277

and http://xdaforums.com/showpost.php?p=53077937&postcount=281

6. Stock Based ROMs ask to flash the Stripped FTF via flashtools in the END, if we keep Stock based ROMs as Secondary ROMs then how will it work then, it will wipe other ROMs Kernal and bootmenu kernal?

Answ - Its Hard but http://xdaforums.com/showpost.php?p=53150024&postcount=325

and http://xdaforums.com/showpost.php?p=53150187&postcount=326

7. Power Off Charging?

Answ - http://xdaforums.com/showpost.php?p=53144286&postcount=322

8. The partition made by Multi Boot for other ROMs is very small, Why is that? Can it be increased?

Answ - http://xdaforums.com/showpost.php?p=53116039&postcount=313

and http://xdaforums.com/showpost.php?p=53118687&postcount=316

and http://xdaforums.com/showpost.php?p=53118722&postcount=317

9. I want to change the name of "mainrom" and Secondary ROM names in boot menu?

Answ - http://xdaforums.com/showpost.php?p=53107296&postcount=307

10. Gapps on Primary ROM?

Answ - http://xdaforums.com/showpost.php?p=53027261&postcount=240

11. Main ROM Update / MainROM Kernal Change?

Answ - http://xdaforums.com/showpost.php?p=53565558&postcount=571