Here are some Boot keys for MICROMAX mobiles for direct USB work
X368 press 1 or green key before connect
X660 volume down key press befor insert data cable for sw
X283 press 0 no. key before connect flashing cable (select USB in comport)
A73 : Both keys home and back, before insert cable,
A78 : Volume UP key, before insert cable.
X271: Press Green/calling key before insert download cable.
X1i reloaded : press calling/green key before download.
X640 : SW with volume Upkey and normal USB
X256,X257 : X11i flashing cable, press calling key
X275 : normal USB, data cable,LSK need to press
X335 : Data cable3, with Calling key
X246 : cable is common with X11i and X550.( Need to press 0 to start, hold and press * key while sw update)
X223 Flashing : X11i cable, Green key for downloading
X78 : Data cable, green key pressing for software update.
Q85: Data Cable-3,RSK need to press.
X312 Flashing : X11i flashing cable , 0 key need to press
X259 : X11i Flashing cable ,Green/calling key need to press.
X210+ Flashing : Calling key + Normal USB cable
X445 Flashing : X11i Flashing cable with center key pressing.
X44 Flashing :X11i Flashing cable ,RSK need to press(data cable with 0 key)
A50 : Data Cable-3,Volume down key
X277 :Flashing cable, LSK need to press for flashing.
X234 :Flashing cable, * (Star)key need to press
A84 Flashing : Copy SW in blank memory card, insert in phone, switch on with pressing Volume UP + Down keys together, SW starts automatically.
X294 Flashing : With cable, LSK key need to press while flashing.
X276 Flashing : Data cable with 1 key press.
X291 : cable is common with X11i and X550.( Need to press * to start, hold and press * key while sw update)
X268 : Flash with X11i cable, # key need to press before connecting cable.
Q34 :X11i Flashing cable ,Call key need to press
X50 : Data cable, LSK Key
X331 :Flashing cable, Press Calling key for downloading.
A56 : THROUGH MMC ,PRESS UP ARROW KEY+VOL UP KEY
X275 : LSK Key, Flashing cable
X278 : Data Cable, Press '1' key before connect cable for Downloading to make USB COM PORT.
A57,A87: Copy and paste SW folder in memory card, extract or wo extract, Volume UP key + Power ON to start download.
A84: Copy and paste SW folder in memory card,extracted SW files, VolumeUP+Down+ Power ON key to start download.
X101,X103 : Flashing with Data cable(LSK),write IMEI in tool, press write, insert cable in phone w/o battery, then at last insert battery in phone.Sample passed
X331i(6250A) :LSK KEY need to press before insert Data cable3.
X234C : 'Music' key need to press before connect to DATA CABLE-3 or X11i Flashing cable for Flashing.
P350 ress Vol+ and on/off switch inset the data cable hold the Vol+ & through On/off switch give the puls
A101 : Plug in data cable while pressing the volume + key in the phone
A110 : Plug in data cable.
X234+ : Use cable for Flashing, Press '1' key before insert cable for flashing or IMEI write.
A25 : B Type Micro USB (SPAMOB3592) , no shortcut key, insert cable directly for software download.
X210+ : Flashing with Data cable, shortcut key for COM PORT making is Calling(green) key.
X269: flashing cable with Key press LSK
Thanks Jyoti
X368 press 1 or green key before connect
X660 volume down key press befor insert data cable for sw
X283 press 0 no. key before connect flashing cable (select USB in comport)
A73 : Both keys home and back, before insert cable,
A78 : Volume UP key, before insert cable.
X271: Press Green/calling key before insert download cable.
X1i reloaded : press calling/green key before download.
X640 : SW with volume Upkey and normal USB
X256,X257 : X11i flashing cable, press calling key
X275 : normal USB, data cable,LSK need to press
X335 : Data cable3, with Calling key
X246 : cable is common with X11i and X550.( Need to press 0 to start, hold and press * key while sw update)
X223 Flashing : X11i cable, Green key for downloading
X78 : Data cable, green key pressing for software update.
Q85: Data Cable-3,RSK need to press.
X312 Flashing : X11i flashing cable , 0 key need to press
X259 : X11i Flashing cable ,Green/calling key need to press.
X210+ Flashing : Calling key + Normal USB cable
X445 Flashing : X11i Flashing cable with center key pressing.
X44 Flashing :X11i Flashing cable ,RSK need to press(data cable with 0 key)
A50 : Data Cable-3,Volume down key
X277 :Flashing cable, LSK need to press for flashing.
X234 :Flashing cable, * (Star)key need to press
A84 Flashing : Copy SW in blank memory card, insert in phone, switch on with pressing Volume UP + Down keys together, SW starts automatically.
X294 Flashing : With cable, LSK key need to press while flashing.
X276 Flashing : Data cable with 1 key press.
X291 : cable is common with X11i and X550.( Need to press * to start, hold and press * key while sw update)
X268 : Flash with X11i cable, # key need to press before connecting cable.
Q34 :X11i Flashing cable ,Call key need to press
X50 : Data cable, LSK Key
X331 :Flashing cable, Press Calling key for downloading.
A56 : THROUGH MMC ,PRESS UP ARROW KEY+VOL UP KEY
X275 : LSK Key, Flashing cable
X278 : Data Cable, Press '1' key before connect cable for Downloading to make USB COM PORT.
A57,A87: Copy and paste SW folder in memory card, extract or wo extract, Volume UP key + Power ON to start download.
A84: Copy and paste SW folder in memory card,extracted SW files, VolumeUP+Down+ Power ON key to start download.
X101,X103 : Flashing with Data cable(LSK),write IMEI in tool, press write, insert cable in phone w/o battery, then at last insert battery in phone.Sample passed
X331i(6250A) :LSK KEY need to press before insert Data cable3.
X234C : 'Music' key need to press before connect to DATA CABLE-3 or X11i Flashing cable for Flashing.
P350 ress Vol+ and on/off switch inset the data cable hold the Vol+ & through On/off switch give the puls
A101 : Plug in data cable while pressing the volume + key in the phone
A110 : Plug in data cable.
X234+ : Use cable for Flashing, Press '1' key before insert cable for flashing or IMEI write.
A25 : B Type Micro USB (SPAMOB3592) , no shortcut key, insert cable directly for software download.
X210+ : Flashing with Data cable, shortcut key for COM PORT making is Calling(green) key.
X269: flashing cable with Key press LSK
Thanks Jyoti