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I am building the android source code and getting new system.img . I try to flash the new system.img on a device and I see that I need another file called boot.img. What is this file ? what is used for ? how can I get it for my device ?

Foad Rezek
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1 Answers1

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boot.img contains the kernel and ramdisk, critical files necessary to load the device before the filesystem can be mounted. You have to generate the boot.img yourself using mkbootimg, a tool provided by AOSP.

All the details you need are available at this xda-developers thread.

This google discussion thread may also be useful

rcbevans
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    Just a question: if I flash a wrong boot.img on a samsung device, will I still be able to access download mode? – Vinz243 Jan 14 '15 at 12:24
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    Yes, download mode is programmed into the devices read only memory and so boot.img doesn't touch it. The boot.img is part of the Android ROM you flash onto your device. Download mode is there to make it *almost* impossible to brick your device as used to be possible when using custom ROMs in the early days of Android – rcbevans Jan 14 '15 at 16:29
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    I flashed a wrong boot.img and can't access download mode using three button combination. Would a USB Jig work? – David Refoua Nov 08 '16 at 23:57