32L496GDISCOVERY: does not start USB serial

[ponyatov]

board: 32L496GDISCOVERY (STM32L496G-DISCO)
   fw: espruino_2v25_stm32l496gdiscovery.bin
  md5: d65362c06d1d9d2ed2a3bcb5dd2c17ce

problem: Espruino console does not start after firmware load via USB drive

only programmer appears in device list after full reconnect & reset:

Bus 003 Device 004: ID 0483:374b STMicroelectronics ST-LINK/V2.1

[18196.852601] usb 3-4: USB disconnect, device number 3
[18199.944227] usb 3-4: new full-speed USB device number 4 using xhci_hcd
[18200.097809] usb 3-4: New USB device found, idVendor=0483, idProduct=374b, bcdDevice= 1.00
[18200.097822] usb 3-4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[18200.097826] usb 3-4: Product: STM32 STLink
[18200.097830] usb 3-4: Manufacturer: STMicroelectronics
[18200.097832] usb 3-4: SerialNumber: 066FFF323532543457213605
[18200.155999] usb-storage 3-4:1.1: USB Mass Storage device detected
[18200.156191] scsi host6: usb-storage 3-4:1.1
[18200.156886] cdc_acm 3-4:1.2: ttyACM0: USB ACM device
[18201.188921] scsi 6:0:0:0: Direct-Access     MBED     microcontroller  1.0  PQ: 0 ANSI: 2
[18201.189367] sd 6:0:0:0: Attached scsi generic sg2 type 0
[18201.190395] sd 6:0:0:0: [sdb] 2120 512-byte logical blocks: (1.09 MB/1.04 MiB)
[18201.190647] sd 6:0:0:0: [sdb] Write Protect is off
[18201.190655] sd 6:0:0:0: [sdb] Mode Sense: 03 00 00 00
[18201.190811] sd 6:0:0:0: [sdb] No Caching mode page found
[18201.190817] sd 6:0:0:0: [sdb] Assuming drive cache: write through
[18201.209306] sd 6:0:0:0: [sdb] Attached SCSI removable disk

[gfwilliams]

Not sure what to suggest here - I only actively work on the F1/F4 ports as those are in the boards I use. The 32L496 port was done by ST themselves

Does the LED flash? Is there comms via USB? That would verify that Espruino is at least running.

What if you power it from the other USB and then connect the USB for the MCU after it has booted? And just to check, how about rebooting with BOOT0 reset - that should put it into bootloader mode which will at least verify the USB connection works.