Lopy4 serial connection troubleshooting

[Re]

Hello everyone,
I just received two LoPy4, as well as one expansion board.

Trying to access the LoPy4 via Serial, I have troubles sending it command.

It seems I can receive data just fine, but I cannot send data to the LoPy4 module.
What I receive is the following, using screen /dev/ttyACM0 115200

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff9010,len:12
ho 0 tail 12 room 4
load:0x3fff9020,len:388
load:0x40078000,len:11584
load:0x4009fb00,len:848
entry 0x4009fc9c
MicroPython v1.8.6-798-gebbcca48-dirty on 2017-10-31; LoPy4 with ESP32
Type "help()" for more information.
>>> 

So it looks like the board is working fine, but yet I cannot enter data, I cannot type enter, etc.

Any idea what I might do wrong?

Thank you

[Re]

I found out what was the problem: not the cable, not the up to date expansion board3, but simply the out-of-date lopy4 firmware.

Updating it fixed it!

[robert-hh]

@re
a) check the cable, if it is a full USB cable or just a charging cable
b) check the jumpers on the expansion board. At least the RX and TX junpers must be in place
c) you might need to update the frmware of the expansion board. I assume you are using expansion board 3, since you just received it.