ESP8266 Community Forum

It could also be that
- the flash was created for that size and is referencing the wrong user_init and certificate flash locations
- the locations the OP used to flash the above were not correct for the larger flash size

softfoot wrote:The chip is a 25Q32 and is reported as 32Mb so I tried 32Mbit-C1 ---- on a reboot all I got out of the serial port was garbage.

In the end after going around in circles web searching and getting conflicting info on the meaning of the "-C1" I tried the 16Mbit-C1 settings and it worked!

So, my question is given my chip is a 25Q32 why on earth do I have to use 16Mbit-C1 ???

I have just received answer to this, from another person:

I think the 1.7 'prebuild' binaries are for 16Mbit flash,
and the esptool would flash it right with addresses for 16Mbit flash.

So this might be the end for this.
Espressif seems to be really problematic when it comes to trusting them with Firmwares..

@Rudy: Well that was a really useless explanation
@Spaceman: Let's praise him for the useless explanation.

Anyways. I had the same question and found some info. From the Flash Download Tool User Guide

"FLASH SIZE: size of the flash being used in Mbits (For ESP8266, 16Mbit-C1 means
that the flash mapping is 8 Mbit + 8 Mbit, and 32 Mbit-C means 4 Mbit + 4 Mbit)

This means that some 16Mbit devices have a contiguous 16Mbit memory space whereas others have a 8Mbit + 8Mbit memory space. So how do you know? Unless we can physically see the writing on the SPI flash chip and then get its datasheet, there is no real way Maybe there is a mapping for the flash devID reported by the Flash Download Tool that can give us more insight into what device is actually populated on the board. Or maybe the Flash Download Tool will explicitly tell you when it is a C1 device. But I'm not certain since mine is only reporting: flash devID: 4015h QUAD; 16Mbit. I will post again when I have more info.