Have a Hex File For Unknown AVR Chip. Can we find Chip Form Hex Code?

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Hello,

I have a hex code it is 90K the person is using HIDBootFlash to load it via USB to the AVR

Anyway to tell form the hex code what AVR Chip they are using?

Unit uses a small 96×96 oled i2C display.

Thanks

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Last Edited: Sun. Mar 21, 2021 - 01:22 AM
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Do you know for sure it's for AVR? 91K hex or bytes?If the later then it would need to be at least a 128K chip.

 

But unless the coder put the chip name into the code somehow it maybe impossible to find out.

John Samperi

Ampertronics Pty. Ltd.

https://www.ampertronics.com.au

* Electronic Design * Custom Products * Contract Assembly

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You can try. Analyze the size of vector table at the beginning of HEX, try to locate fragments responsible for SP initialization – so at least you will know the size of SRAM and vector table, so you will be able to narrow the search. If it is still not enough you can disassemble the code and try to analyze how app refers to IO registers. It can give you a hint about used MCU.

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I've thrown some tools at this and it doesn't make much sense.

This is what resides at the reset vector:

 

 

Looks like random stuff, there should be a vector table there. Is it encrypted?

This forum is not an hacking service, you know...

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That Hex is not AVR code.

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>I have a hex code it is 90K

 

It may be a 90K file but the hex file shows it is using addresses 0-0x7FFF, so the data the hex file represents is 32k. Its also quite odd that the whole 32k of data is filled up with no erased bytes on the end (plus the data makes no sense). You have some form of encrypted hex file that the bootloader on the mcu is decrypting. Hex file does you no good even if you know what avr is being used.

 

>what AVR Chip they are using?

 

Something that has >32k of flash. 32k of hex data (app) + hid bootloader.

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Thanks.