New board with WROVER doesn't produce WiFi network - is 16MB flash empty?

[jcsbanks]

We have changed our custom PCB from WROOM to WROVER, and some prototypes have just been assembled. The UART has yet to be probed (the board and I are in different countries), but 3V3, EN and IO0 are as expected and no WiFi network is being hosted like would happen with a new WROOM.

The WROVER modules are from TME and have 16MB flash and 8MB PSRAM.

Is the 16MB flash variant likely to have no firmware on it or are we looking at an electronic problem?

IO15 is pulled down so we would not expect bootloader chatter on the UART, but if there is firmware on the flash we should expect some chatter from the standard firmware after that?

Some UART tests will be done and compared against WROOM later.

[loboris]

All WROOM and WROWER modules I've ever bought came with empty (erased) Flash, no firmware loaded.
Some sellers or board manufacturers may preload some firmware, but this should not be the case with bare WROOM/WROVER modules, no metter if it is 4,8 or 16MB.

[jcsbanks]

Thanks, I just did make erase_flash on a WROOM and when it boots it shows this in a loop:
rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
flash read err, 1000
ets_main.c 371
ets Jun 8 2016 00:22:57

and transmits no WiFi network.

However, other WROOM modules when powered up on a custom PCB show up as a WiFi network. Without having flashed them, nor the guy who put them on the PCB having flashed them. So now I'm more confused by what you say and what I observe, and whether I have a problem or not. I'll have to get him to actually flash something onto them to test it seems, which is a surprise given previous experiences with WROOM.

[loboris]

Not only it wouldn't make much sense selling the modules with some preprogrammed demo application (wich will be erased by the user anyway), the price (time) to flash the application on milions of modules would make them much more expensive.

[jcsbanks]

The WROVER does go into programming mode when IO0 is held low, so that is promising and will test more when the EE is available.

I thought I was going mad, but the EE sent me pictures of UART dumps of some WROOM modules (new, bare, soldered onto a board by him) that show 2nd stage bootloader, partition table and WiFi. It seems there is a test flash in some modules, but it making a WiFi network is not a reliable test as three examples of this WROVER do not.