ESP32-S2 WROVER module bottom GPIO not working

[allenpan]

ESP32-S2 WROVER module bottom GPIO not working

from GPIO_14-GPIO_26, not working, I used the following example:

GPIO example: the GPIO (default output 18 and 19), from scope i dont see any output
UART echo example: the GPIO 17, 18 default as UART1 TX/RX
USB CDC example: the default USB pin 19/20

all of those example with its default setting i cant get those pins to work, I tired with ESP32-S2 WROVER and EXP-12K models and different modules can't get them working? is there some where is the menuconfig i need to do?

note: for the UART example, if i use other pins, they works ... ie 8/9, 41/40 ... etc

[allenpan]

UPDATE Problem SOLVED!

the bottom pins are not in perfect contacts, resultant in no output, both Arduino and ESSP-IDF works well!