Thank you! I already had "Make RAM allocatable using malloc() as well", but not That did the trick! I'm up and running again and all is well with the world.
Many thanks!

Yes, I'm short on RAM (the ESP_ERR_NO_MEM is a bit of a clue, grin). The question is how, or why?

There is nothing in my code's memory allocation that's different between using external RAM and not. The only thing different between these two cases is that I enable or disable "Support for external ...

I have WI-FI STA and AP code working properly on an ESP32-S2 WROOM, but when I run it on a WROVER with the external RAM enabled, esp_wifi_init() fails with ESP_ERR_NO_MEM.

The startup code for AP mode:
ESP_ERROR_CHECK(esp_event_loop_create_default());
ESP_ERROR_CHECK(esp_event_handler_instance ...

Interesting: when I build msc_disk.c into the tinyusb component itself (specifically, in components/tinyusb/tinyusb/src/class/msc, alongside msc_device.c), it compiles and links with only the error
region `dram0_0_seg' overflowed by 11808 bytes If I then change the DISK_BLOCK_NUM to 4 instead of 2 ...

Whether I separate it out into its own component or leave it bundled with tusb_sample_msc in libmain.a, the result is exactly the same set of undefined references. (And, FWIW, I have successfully taken files in my own projects' main folders and turned them into separate components, and it's always ...

Its hard to say without more details how do you prepare and build project, which repository you are using etc.
Maybe you are missing msc_disk.c in CMakeLists.txt

Yes, that was my first thought; that would have been an easy fix! Sadly, I already have it included. I'm probably missing some simple ...

Trying to compile the tusb_sample_msc example, but all the tud_ xxx _cb callbacks in msc_disk.c show up as undefined references during the link phase:

/Users/adamwilt/.espressif/tools/xtensa-esp32s2-elf/esp-2020r3-8.4.0/xtensa-esp32s2-elf/bin/../lib/gcc/xtensa-esp32s2-elf/8.4.0/../../../../xtensa ...

I have code, based on the examples, that starts and stops the WiFi stack, tearing it down when stopped. Here's the code for AP mode:

static esp_netif_t *_espNetif;

void wifi_ap_start(int clients) {
esp_event_loop_create_default();
esp_event_handler_instance_register(WIFI_EVENT,
ESP_EVENT_ANY ...

Check out u8g2: https://github.com/olikraus/u8g2

Using it in esp-idf: https://www.lucadentella.it/en/2017/10/30/esp32-25-display-oled-con-u8g2/

Here are the necessary "hal" files in the Kolban repository:
https://github.com/nkolban/esp32-snippets/tree/master/hardware/displays/U8G2
The test files ...

I'm trying to build wifi AP and STA modes that I can start and stop at will.

I call esp_netif_init() once, at startup.

Then I start up wifi using code similar to this simplified pseudocode:
_espNetif = esp_netif_create_default_wifi_[ap|station]();
esp_wifi_init();
esp_wifi_set_mode();
esp ...