kondaveetiarungopal
Posts: 88
Joined: Fri Apr 26, 2013 6:35 am

creation of bootcode.bin and start.elf and loaer.bin

Fri Aug 16, 2013 6:13 pm

Hi,

i was work on raspberry pi..when i was studying about the raspberry pi booting process..i got a one dought..for booting a raspberry pi u need these type of bootloaders like bootcode.bin and start.elf and loader.bin..how these are come from?i mean what type of programing are u using for developing a bootloade.bin and start.elf and loader.bin..how to develop these from scratch..what type of process can i follow to develop a these type of bootloaders...and one morething there are lot of bootloaders are available like uboot and MLO..can i use these type of bootloaders on raspberry pi?how to customise these type of bootloaders..please give me reply...

RobHenry
Posts: 452
Joined: Fri Sep 21, 2012 9:04 pm
Location: UK

Re: creation of bootcode.bin and start.elf and loaer.bin

Fri Aug 16, 2013 7:06 pm

Those files control the initial boot process and contain the GPU binary blob (firmware, effectively). They are Broadcom closed source so you won't be developing them yourself, I'm afraid.

You shouldn't have to browse the forum for long to find a wealth of information and discussion about these files and the firmware in general.

User avatar
ShiftPlusOne
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 6386
Joined: Fri Jul 29, 2011 5:36 pm

Re: creation of bootcode.bin and start.elf and loaer.bin

Fri Aug 16, 2013 7:31 pm

However, there is an effort to reverse engineer these binaries. https://github.com/hermanhermitage/videocoreiv

If your country's allow, you can disassembled them and poke around, but it's hell of a lot of code.

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 31371
Joined: Sat Jul 30, 2011 7:41 pm

Re: creation of bootcode.bin and start.elf and loaer.bin

Fri Aug 16, 2013 7:35 pm

ShiftPlusOne wrote:However, there is an effort to reverse engineer these binaries. https://github.com/hermanhermitage/videocoreiv

If your country's allow, you can disassembled them and poke around, but it's hell of a lot of code.
I have access to the source code (as I work at Broadcom), and the sheer quantity of it scares me! There must be going on a million lines of code just in the GPU.
Principal Software Engineer at Raspberry Pi Ltd.
Working in the Applications Team.

User avatar
ShiftPlusOne
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 6386
Joined: Fri Jul 29, 2011 5:36 pm

Re: creation of bootcode.bin and start.elf and loaer.bin

Fri Aug 16, 2013 8:00 pm

jamesh wrote: I have access to the source code (as I work at Broadcom), and the sheer quantity of it scares me! There must be going on a million lines of code just in the GPU.
I suppose most of that is not essential, like support for opengl es, openmanx and so on. If they can get to a stage where they can initialize the basic hardware and hand control over to the ARM, that should be more than enough for many people. Though they seem to be focusing more on running vc kernels from within linux, rather than trying to replace the binaries... which seems like the smart thing to do, since there's no point re-inventing the wheel.

Anyway, you should contribute to the project :roll: :)

kondaveetiarungopal
Posts: 88
Joined: Fri Apr 26, 2013 6:35 am

Re: creation of bootcode.bin and start.elf and loaer.bin

Sat Aug 17, 2013 7:49 am

Hi,

thanks to everyone who are given reply for this post..what iam want is how these files are come into picture i mean every source bootloader having a one source file..i want that source file for bootcode.bin and start.elf file and loader.bin files...how these files are come into picture with source..i want source files for this....i mean suppose take a beagle board for this board there bootloaders are available like uboot and mlo..these type of bootloaders are available to customise and to see source files...so like this what type of source file is used for developing bootcode.bin and start.elf and loader.bin...i want this information only...

ghans
Posts: 7893
Joined: Mon Dec 12, 2011 8:30 pm
Location: Germany

Re: creation of bootcode.bin and start.elf and loaer.bin

Sat Aug 17, 2013 8:00 am

Well ,
Broadcom is not interested in releasing source , documentation
or toolchains for it (not for free , that is). I doubt the
foundation is interested in it , too. It does work , and dom
does an astounding job fixing bugs.

It is simply a trade secret , and Broadcom will not even talk to
you if you're not a company which has lots of money on your
bank account.
And of course , you should be willing to spend some of those
millions. I don't think they are motivated to spill their secrets
without an reasonably-sized order of BCM2835 chips.

You could have a look at piface ... i'm not sure if
you can really boot the ARM with it , though.

ghans
• Don't like the board ? Missing features ? Change to the prosilver theme ! You can find it in your settings.
• Don't like to search the forum BEFORE posting 'cos it's useless ? Try googling : yoursearchtermshere site:raspberrypi.org

User avatar
Burngate
Posts: 6536
Joined: Thu Sep 29, 2011 4:34 pm
Location: Berkshire UK Tralfamadore

Re: creation of bootcode.bin and start.elf and loaer.bin

Sat Aug 17, 2013 10:36 am

Not sure this helps, but ...
When your average PC gets switched on, the CPU starts off reading the BIOS rom, which tells it how to read a disc, from which it gets the rest of its working code. You can change the code in the BIOS, or you can add stuff to the disc, all in x86 code.

When the Pi is first powered up, it isn't an ARM computer, it's a GPU that can read an SD card.
Only when start.elf has been read does the ARM get fired up.
So to alter what bootcode.bin or start.elf does, you need to understand the GPU.

Which means your name has to be Dom or James

User avatar
rpdom
Posts: 20381
Joined: Sun May 06, 2012 5:17 am
Location: Chelmsford, Essex, UK

Re: creation of bootcode.bin and start.elf and loaer.bin

Sat Aug 17, 2013 10:41 am

Burngate wrote:Which means your name has to be Dom or James
I wish it were that simple...

(rp)Dom ;-)

jamesh
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 31371
Joined: Sat Jul 30, 2011 7:41 pm

Re: creation of bootcode.bin and start.elf and loaer.bin

Sat Aug 17, 2013 12:15 pm

rpdom wrote:
Burngate wrote:Which means your name has to be Dom or James
I wish it were that simple...

(rp)Dom ;-)
Me too. In fact, it's just Dom - he knows almost everything.

And in answer to an earlier question, I am not allowed to take part in the OSS/reverse engineering project - that would result in instant dismissal, and I need a job!
Principal Software Engineer at Raspberry Pi Ltd.
Working in the Applications Team.

User avatar
ShiftPlusOne
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 6386
Joined: Fri Jul 29, 2011 5:36 pm

Re: creation of bootcode.bin and start.elf and loaer.bin

Sat Aug 17, 2013 12:18 pm

It was worth a shot.

Return to “Raspberry Pi OS”