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Update nuke.c to auto-detect flash size #653

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Update nuke.c to auto-detect flash size #653

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11 changes: 5 additions & 6 deletions flash/nuke/nuke.c
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Original file line number Diff line number Diff line change
Expand Up @@ -27,12 +27,11 @@

int main() {
uint flash_size_bytes;
#ifndef PICO_FLASH_SIZE_BYTES
#warning PICO_FLASH_SIZE_BYTES not set, assuming 16M
flash_size_bytes = 16 * 1024 * 1024;
#else
flash_size_bytes = PICO_FLASH_SIZE_BYTES;
#endif
uint8_t txbuf[4];
uint8_t rxbuf[4];
txbuf[0] = 0x9f;
flash_do_cmd(txbuf, rxbuf, 4);
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Is this guaranteed to work with every variety of SPI Flash chip that might be used with RP2040 or RP2350?

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It's a good question. I was under the dangerous assumption that they all follow a standard query for that information, like the JEDEC command used. Of course just because JEDEC claims "Global Standards for the Microelectronics Industry", it's plausible for non compatible things to be used by more adventurous souls.

I'm not an expert on this matter.

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I'm not an expert on this matter.

Me neither! The only reason I asked, was because I assumed that if it was universally supported, then there'd already be a wrapper-function for it in pico-sdk? 🤔
But that's merely a hunch, I could be entirely wrong! 🙊

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This suggests for an FPGA situation with NOR flash that two possible command sets exist, but I've no idea if that first option is supported by RP2s.
https://electronics.stackexchange.com/a/673366

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@tyeth tyeth Jun 18, 2025 •
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Okay, so digging deeper, yes the Serial Flash Discovery Protocol spec also mandates the backwards compatible support for 0x9f command from the Common Flash Interface, or at least as far as my limited research indicates.

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cc @Wren6991 who i believe has said in the past that such a command is not universally supported

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Try it- with fall back to 2MB or 4MB depending on chip? (Though it would probably be Pico boards where it works)

That said it’s kinda up to the vendor to verify flash_nuke works on their board and - if not - supply a customised alternative.

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That said it’s kinda up to the vendor to verify flash_nuke works on their board and - if not - supply a customised alternative.

😂 🤣 😂 🤣 😂 🤣

If every vendor provided even half of the support that Pimoroni did, the world would be a much better place 😀

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@Wren6991 any thoughts, or objections?

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Maybe there is a known case of returning wrong info, so some default would be wiser...
https://github.com/adafruit/circuitpython/blob/ffc42b9f0f4aa5e812de5302bc217e1dd5a0f8b6/ports/raspberrypi/supervisor/internal_flash.c#L81C35-L89C6

flash_size_bytes = 1u << rxbuf[3];
flash_range_erase(0, flash_size_bytes);
// Leave an eyecatcher pattern in the first page of flash so picotool can
// more easily check the size:
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