A silly question about the firmware update method

December172

34
A student interested in the Canon P&S hack

A silly question about the firmware update method

« on: 24 / October / 2022, 20:16:08 »

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Hi,guys.
This is my first post,if I placed it wrong pls move it,thanks.
When I load CHDK in firmware method,I got something like "Update firmware version? 1.0.0.0 -> 1.1.0.0"
In this,I know the 1.0.0.0 is my firmware version,but what is the 1.1.0.0? Is that the CHDK encoding process's information? Can we modifiy it to something else(like the CHDK version,etc)
Any answer is appreciated!
Thx

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Canon PowerShot ELPH 180 (IXUS 175).
(Seems most of you are older than me.... Anyone teen? )

reyalp

14110

Re: A silly question about the firmware update method

« Reply #1 on: 25 / October / 2022, 01:16:33 »

Quote from: December172 on 24 / October / 2022, 20:16:08

Hi,guys.
This is my first post,if I placed it wrong pls move it,thanks.
When I load CHDK in firmware method,I got something like "Update firmware version? 1.0.0.0 -> 1.1.0.0"
In this,I know the 1.0.0.0 is my firmware version,but what is the 1.1.0.0?

It's just a field that needs to be set in the firmware file.

Code: [Select]

Is that the CHDK encoding process's  information? Can we modifiy it to something else(like the CHDK version,etc)
[/quote]
For PS.FI2 files, the version is set in tools/packfi2/fi2enc.c
[code]
 hdr.id=0x01010000;

Changing that to, say 0x01020000 shows 1.2.0.0

For vxworks cams that use PS.FIR, it should be settable in the main Makefile in the line

Code: [Select]

$(PAKWIF) $(FW_UPD_FILE) $(bin)/main.bin $(TARGET_PID) 0x01000101

The source for this tool is tools/pakwif.c

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Don't forget what the H stands for.

December172

34
A student interested in the Canon P&S hack

Re: A silly question about the firmware update method

« Reply #2 on: 25 / October / 2022, 19:59:43 »

Thanks for reply!
There's one another thing that I want to figure out: How to get a valid FI2KEY? I've tried the disassembly.pl and extract.py script,but I can only get a FI2IV,the FI2KEY segment is blank.
Is that my way incorrect? If so,please tell me the way to get correct FI2KEY and FI2IV.(in my condition,on a Ubuntu computer,and don't have a Windows environment)
My platform is IXUS 175(ixus175_elph180)
Thx.

Logged

Canon PowerShot ELPH 180 (IXUS 175).
(Seems most of you are older than me.... Anyone teen? )

reyalp

14110

Re: A silly question about the firmware update method

« Reply #3 on: 26 / October / 2022, 01:40:26 »

Quote from: December172 on 25 / October / 2022, 19:59:43

There's one another thing that I want to figure out: How to get a valid FI2KEY? I've tried the disassembly.pl and extract.py script,but I can only get a FI2IV,the FI2KEY segment is blank. Is that my way incorrect?

Hmm, yes, extract.py probably doesn't work correctly on newer cams like ixus175.

Quote

If so,please tell me the way to get correct FI2KEY and FI2IV.(in my condition,on a Ubuntu computer,and don't have a Windows environment)
My platform is IXUS 175(ixus175_elph180)

You could go to https://chdk.fandom.com/wiki/For_Developers/fi2offsets and get the values from a known firmware using the same "encoding" (KEYSYS in CHDK makefiles) value in the firmware dumps archive, or more generally, find it in a known dump and then locate the equivalent disassembly in yours.

But for ixu175, the offset of FI2KEY is 0x2968 and FI2IV is 0x4fecec. This should be correct for all known canon firmware variants.

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Don't forget what the H stands for.

December172

34
A student interested in the Canon P&S hack

Re: A silly question about the firmware update method

« Reply #4 on: 26 / October / 2022, 03:31:50 »

Success!
I've modified the key_addr in extract.py to the real FI2KEY address in my firmware dump file ,and I get a usable FI2KEY and FI2IV.Now I can modify the firmware update screen displayed version.
Thanks again for that useful information!

Logged

Canon PowerShot ELPH 180 (IXUS 175).
(Seems most of you are older than me.... Anyone teen? )