Yes the missing MCU Version might be a clue.
Found another gateway prototype that did work:
root@swi-mdm9x28-wp:~# cm info
Device: WP7607-1
IMEI: 359780080485307
IMEISV: 6
FSN: VP918600371310
Firmware Version: SWI9X07Y_02.28.03.03 000000 jenkins 2019/05/21 03:33:04
Bootloader Version: SWI9X07Y_02.28.03.03 000000 jenkins 2019/05/21 03:33:04
MCU Version: 002.011
PRI Part Number (PN): 9908664
PRI Revision: 001.001
Carrier PRI Name: GENERIC
Carrier PRI Revision: 002.068_000
SKU: 1104193
Last Reset Cause: Power Down
Resets Count: Expected: 430 Unexpected: 0
root@swi-mdm9x28-wp:~# echo 36 > /sys/class/gpio/export
root@swi-mdm9x28-wp:~# echo 37 > /sys/class/gpio/export
root@swi-mdm9x28-wp:~# echo 38 > /sys/class/gpio/export
And then another gateway from our mass production that did not work:
Gateway with new PCB:
root@swi-mdm9x28-wp:~# cm info
Device: WP7607-1
IMEI: 359780080541927
IMEISV: 6
FSN: VP919600061110
Firmware Version: SWI9X07Y_02.28.03.03 000000 jenkins 2019/05/21 03:33:04
Bootloader Version: SWI9X07Y_02.28.03.03 000000 jenkins 2019/05/21 03:33:04
MCU Version:
PRI Part Number (PN): 9908664
PRI Revision: 001.001
Carrier PRI Name: GENERIC
Carrier PRI Revision: 002.068_000
SKU: 1104193
Last Reset Cause: Reset, User Requested
Resets Count: Expected: 55 Unexpected: 0
Nov 13 08:49:34 swi-mdm9x28-wp user.err Legato: =ERR= | powerManagerService[886]/powerMgr T=main | le_ulpm.c le_ulpm_GetFirmwareVersion() 417 | Unable to open file /sys/module/swimcu_pm/firmware/version for reading (No such file or directory). Wrong platform/mcu-firmware