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Kiosk provider seeking an 8051 assembly language developer to patch firmware to: * Add two i2c commands: 1-turn on 2-turn off Notes: 1. Device has pre-existing soft power control. 2. Device has pre-existing operational I2C interface. 3. Current firmware is available only as ROM image. 4. We -possibly- have some C source code for the 8051-based controller, but it is not configured for the product, nor includes past manufacturer provided customizations. It is probably mostly useful as a reference tool. Deliverable Requirements 1. ROM image: a. With new I2C on/off command functionality. b. Upon boot, the device must start in the existing on state. c. All existing functionality must still be operational. d. Provided in the same ROM-able Intel hex format the original firmware image was supplied in. 2. New functionality in deliverable #1 must pass 100 I2C command off/on test cycles. 3. Assembly language listing for deliverable #1, with descriptive comments documenting changes. 4. Deliverables must be provided within 6 business days from when both parties agree to commencement of work. Available Resources We can provide for the duration of the work: * One controller board for development/testing. -and- * One end-product module which uses the controller board. Work Quotation Please e-mail: * Your all-in fixed price for the work. * Relevant qualifications. * The option of partial payment mid-way through project requires two strong references. Otherwise, payment is upon receipt of the required deliverables.
Note that you can find 8051 chips with at least 1MB of code flash. So way, way larger would, in my language, mean that you have disassembled at least 10MB+ binaries.
But one thing to note is that huge binaries are normally generated from a high-level language. While 8051 binaries can contain very tricky code written all in assembler to get the most out of the chip. Tricky code includes situations where the same byte can be both data and code. That isn't something a compiler would produce. Tricky code may require that you need to know the allowed value range stored in specific registers to be able to deduce the behaviour - and that isn't so easy even for a multi-pass disassembler.
In this case, we know that there may be some C source code in existence. But that doesn't prove that this in original the code was 100% C. A significant part could be in assembler, and written by a wicked developer willing to use any trick in the book to squeeze an extra clock cycle or byte.
No sane human with the proper skills to understand the issues would enters a fixed-price contract with a fixed deadline based on so much unknowns. Only a fool or a troll (which is just another type of fool) would jump at it.
Certainly in excess of a few MB. Haven't you?
Per, please stop being such a pompous git.
Richard Marshall BEng(Hons)
"But that doesn't prove that this in original the code was 100% C"
My reading of the original post is that the 'C' is definitely not the source of the available image.
"written by a wicked developer"
Well, the lack of source code is certainly a Big Red Light!
At the very least, it shows a hopless lack of development process.
What other important design information is also going to be missing...?
Something is seriously wrong if there is a need to make a total reverse engineering of a multi-MB project.
Unless the goal is to steal someone elses code, most situations where reverse engineering is needed would relate to quite small blocks within a larger binary. Such as the interfacing of the binary with a specific hardware device, to allow totally new code to be written for existing, but badly documented hardware.
Small fixes for a binary with missing source code is normally produced by patching in new code at the end of the binary and just patch the existing binary to access this new code.
Large fixes for a binary with missing source code? Normally solved by rewriting everything. Or suggest that the hardware is old enough that it is better to make a completely new product with new electronics and get a product where the customer both owns documented source code, and have a cheaper hardware platform to produce and sell for possibly quite a number of years.
In the end, reverse-engineering of larger projects is normally a huge fail. Wrong route to solve a problem after having already huge fail of losing the source code.