Im having a similar issue but cannot confirm it is power supply related in my case. I'm using the power supply and LiPO charge circuit taken off of the Sparkfun ESP32 Thing. I confirmed it is able to supply the WROOM by connecting to a ESP32 Dev Module 3V3 and Gnd pins directly. I am reading serial through a separate FTDI interface and confirmed it is able to run my WiFi examples without issue. However, when I try to run the WiFi.begin(ssid,pw) command on my simplified WROOM breakout, I get the same InstrFetchProhibited errors discussed here previously. Specific backtrace is here:
0x4008c6c6: write_txrate_power_offset at ?? line ?
0x40089651: set_tx_gain_table at ?? line ?
0x4008a5c5: bb_init at ?? line ?
0x4008ad93: register_chipv7_phy at ?? line ?
0x4010abc0: esp_phy_rf_init at /Users/ficeto/Desktop/ESP32/ESP32/esp-idf-public/components/esp32/./phy_init.c line 142
0x4010ad29: esp_phy_load_cal_and_init at /Users/ficeto/Desktop/ESP32/ESP32/esp-idf-public/components/esp32/./phy_init.c line 290
0x400ed6ab: wifi_hw_start at ?? line ?
0x400ed6e9: wifi_start_process at ?? line ?
0x400edc8a: ieee80211_ioctl_process at ?? line ?
0x400946f6: ppTask at ?? line ?
Also here is the schematic of my breakout circuit:
- ESP32_Breakout_Schem.png (100.66 KiB) Viewed 14236 times
Any idea what's different? Perhaps I need a different capacitor closer to the input? Thank you!