[Motorola One Zoom (aka Pro) Questions & Answers] yeetusAAA:
The situation changed slightly since I came back from work.

Previously device appeared as unknown device.

With name "fastboot parker S", I have it in search history.

After rebooting (and installing 50 drivers) my device appears as "Motorola ADB Interface", however execution of commands don't end successfully.

X:\Applications\MinimalADBFB>fastboot -help
usage: fastboot [ <option> ] <command>

commands:
update <filename> Reflash device from update.zip.
Sets the flashed slot as active.
flashall Flash boot, system, vendor, and --
if found -- recovery. If the device
supports slots, the slot that has
been flashed to is set as active.
Secondary images may be flashed to
an inactive slot.
flash <partition> [ <filename> ] Write a file to a flash partition.
flashing lock Locks the device. Prevents flashing.
flashing unlock Unlocks the device. Allows flashing
any partition except
bootloader-related partitions.
flashing lock_critical Prevents flashing bootloader-related
partitions.
flashing unlock_critical Enables flashing bootloader-related
partitions.
flashing get_unlock_ability Queries bootloader to see if the
device is unlocked.
flashing get_unlock_bootloader_nonce Queries the bootloader to get the
unlock nonce.
flashing unlock_bootloader <request> Issue unlock bootloader using request.
flashing lock_bootloader Locks the bootloader to prevent
bootloader version rollback.
erase <partition> Erase a flash partition.
format[:[<fs type>][:[<size>]] <partition>
Format a flash partition. Can
override the fs type and/or size
the bootloader reports.
getvar <variable> Display a bootloader variable.
set_active <slot> Sets the active slot. If slots are
not supported, this does nothing.
boot <kernel> [ <ramdisk> [ <second> ] ] Download and boot kernel.
flash:raw <bootable-partition> <kernel> [ <ramdisk> [ <second> ] ]
Create bootimage and flash it.
devices [-l] List all connected devices [with
device paths].
continue Continue with autoboot.
reboot [bootloader|emergency] Reboot device [into bootloader or emergency mode].
reboot-bootloader Reboot device into bootloader.
oem <parameter1> ... <parameterN> Executes oem specific command.
stage <infile> Sends contents of <infile> to stage for
the next command. Supported only on
Android Things devices.
get_staged <outfile> Receives data to <outfile> staged by the
last command. Supported only on Android
Things devices.
help Show this help message.

options:
-w Erase userdata and cache (and format
if supported by partition type).
-u Do not erase partition before
formatting.
-s <specific device> Specify a device. For USB, provide either
a serial number or path to device port.
For ethernet, provide an address in the
form <protocol>:<hostname>[:port] where
<protocol> is either tcp or udp.
-c <cmdline> Override kernel commandline.
-i <vendor id> Specify a custom USB vendor id.
-b, --base <base_addr> Specify a custom kernel base
address (default: 0x10000000).
--kernel-offset Specify a custom kernel offset.
(default: 0x00008000)
--ramdisk-offset Specify a custom ramdisk offset.
(default: 0x01000000)
--tags-offset Specify a custom tags offset.
(default: 0x00000100)
-n, --page-size <page size> Specify the nand page size
(default: 2048).
-S <size>[K|M|G] Automatically sparse files greater
than 'size'. 0 to disable.
--slot <slot> Specify slot name to be used if the
device supports slots. All operations
on partitions that support slots will
be done on the slot specified.
'all' can be given to refer to all slots.
'other' can be given to refer to a
non-current slot. If this flag is not
used, slotted partitions will default
to the current active slot.
-a, --set-active[=<slot>] Sets the active slot. If no slot is
provided, this will default to the value
given by --slot. If slots are not
supported, this does nothing. This will
run after all non-reboot commands.
--skip-secondary Will not flash secondary slots when
performing a flashall or update. This
will preserve data on other slots.
--skip-reboot Will not reboot the device when
performing commands that normally
trigger a reboot.
--disable-verity Set the disable-verity flag in the
the vbmeta image being flashed.
--disable-verification Set the disable-verification flag in the vbmeta image being flashed.
--unbuffered Do not buffer input or output.
--version Display version.
-h, --help show this message.

X:\Applications\MinimalADBFB>fastboot -getvar current-slot
fastboot: unknown option -- g

X:\Applications\MinimalADBFB>fastboot getvar current-slot
current-slot: a
finished. total time: 0.016s

X:\Applications\MinimalADBFB>fastboot -set-active=a
fastboot: usage: no command

X:\Applications\MinimalADBFB>fastboot --set-active=a
Setting current slot to 'a'...
FAILED (remote failure)
finished. total time: -0.000s

X:\Applications\MinimalADBFB>fastboot getvar current-slot
current-slot: a
finished. total time: 0.000s

X:\Applications\MinimalADBFB>fastboot getvar current-slot
current-slot: a
finished. total time: -0.000s

X:\Applications\MinimalADBFB>fastboot -set-active=a
fastboot: usage: no command

X:\Applications\MinimalADBFB>fastboot --set-active=a
Setting current slot to 'a'...
FAILED (remote failure)
finished. total time: 0.016s

X:\Applications\MinimalADBFB>fastboot reboot bootloader
rebooting into bootloader...
FAILED (command write failed (No such file or directory))
finished. total time: 0.016s

X:\Applications\MinimalADBFB>

About all those "remote" failures, the commands do appear in "Bootloader Logs", and the text is something like:

"cmd: getvar:slot-count" and "cmd: set_active:a". As someone with Android unrelated programming background I see nothing that would indicate an error on the phone.

Manually rebooting to fastboot doesn't change anything, rebooting the device in general doesn't solve the issue.

After rebooting I redid my steps:

X:\Applications\MinimalADBFB>fastboot getvar current-slot
current-slot: a
finished. total time: 0.004s

X:\Applications\MinimalADBFB>fastboot --set-active=a
Setting current slot to 'a'...
FAILED (status read failed (Too many links))
finished. total time: 0.005s

X:\Applications\MinimalADBFB>

Too many links? Corrupted file system?