diff --git a/fastboot/fastboot.cpp b/fastboot/fastboot.cpp
index c5b357c..091b117 100644
--- a/fastboot/fastboot.cpp
+++ b/fastboot/fastboot.cpp
@@ -326,118 +326,83 @@
     // clang-format off
     fprintf(stdout,
 /*           1234567890123456789012345678901234567890123456789012345678901234567890123456 */
-            "usage: fastboot [ <option> ] <command>\n"
+            "usage: fastboot [OPTION...] COMMAND...\n"
             "\n"
-            "commands:\n"
-            "  update <filename>                        Reflash device from update.zip.\n"
-            "                                           Sets the flashed slot as active.\n"
-            "  flashall                                 Flash boot, system, vendor, and --\n"
-            "                                           if found -- recovery. If the device\n"
-            "                                           supports slots, the slot that has\n"
-            "                                           been flashed to is set as active.\n"
-            "                                           Secondary images may be flashed to\n"
-            "                                           an inactive slot.\n"
-            "  flash <partition> [ <filename> ]         Write a file to a flash partition.\n"
-            "  flashing lock                            Locks the device. Prevents flashing.\n"
-            "  flashing unlock                          Unlocks the device. Allows flashing\n"
-            "                                           any partition except\n"
-            "                                           bootloader-related partitions.\n"
-            "  flashing lock_critical                   Prevents flashing bootloader-related\n"
-            "                                           partitions.\n"
-            "  flashing unlock_critical                 Enables flashing bootloader-related\n"
-            "                                           partitions.\n"
-            "  flashing get_unlock_ability              Queries bootloader to see if the\n"
-            "                                           device is unlocked.\n"
-            "  flashing get_unlock_bootloader_nonce     Queries the bootloader to get the\n"
-            "                                           unlock nonce.\n"
-            "  flashing unlock_bootloader <request>     Issue unlock bootloader using request.\n"
-            "  flashing lock_bootloader                 Locks the bootloader to prevent\n"
-            "                                           bootloader version rollback.\n"
-            "  erase <partition>                        Erase a flash partition.\n"
-            "  format[:[<fs type>][:[<size>]] <partition>\n"
-            "                                           Format a flash partition. Can\n"
-            "                                           override the fs type and/or size\n"
-            "                                           the bootloader reports.\n"
-            "  getvar <variable>                        Display a bootloader variable.\n"
-            "  set_active <slot>                        Sets the active slot. If slots are\n"
-            "                                           not supported, this does nothing.\n"
-            "  boot <kernel> [ <ramdisk> [ <second> ] ] Download and boot kernel.\n"
-            "  flash:raw <bootable-partition> <kernel> [ <ramdisk> [ <second> ] ]\n"
-            "                                           Create bootimage and flash it.\n"
-            "  devices [-l]                             List all connected devices [with\n"
-            "                                           device paths].\n"
-            "  continue                                 Continue with autoboot.\n"
-            "  reboot [bootloader|emergency]            Reboot device [into bootloader or emergency mode].\n"
-            "  reboot-bootloader                        Reboot device into bootloader.\n"
-            "  oem <parameter1> ... <parameterN>        Executes oem specific command.\n"
-            "  stage <infile>                           Sends contents of <infile> to stage for\n"
-            "                                           the next command. Supported only on\n"
-            "                                           Android Things devices.\n"
-            "  get_staged <outfile>                     Receives data to <outfile> staged by the\n"
-            "                                           last command. Supported only on Android\n"
-            "                                           Things devices.\n"
-            "  help                                     Show this help message.\n"
+            "flashing:\n"
+            " update ZIP                 Flash all partitions from an update.zip package.\n"
+            " flashall                   Flash all partitions from $ANDROID_PRODUCT_OUT.\n"
+            "                            On A/B devices, flashed slot is set as active.\n"
+            "                            Secondary images may be flashed to inactive slot.\n"
+            " flash PARTITION [FILENAME]\n"
+            "                            Flash given partition only.\n"
+            "\n"
+            "basics:\n"
+            " devices [-l]               List devices in bootloader (-l: with device paths).\n"
+            " getvar NAME                Display given bootloader variable.\n"
+            " reboot [bootloader]        Reboot device.\n"
+            "\n"
+            "locking/unlocking:\n"
+            " flashing lock|unlock       Lock/unlock partitions for flashing\n"
+            " flashing lock_critical|unlock_critical\n"
+            "                            Lock/unlock 'critical' bootloader partitions.\n"
+            " flashing get_unlock_ability\n"
+            "                            Check whether unlocking is allowed (1) or not(0).\n"
+            "\n"
+            "advanced:\n"
+            " erase PARTITION            Erase a flash partition.\n"
+            " format[:FS_TYPE[:SIZE]] PARTITION\n"
+            "                            Format a flash partition.\n"
+            " set_active SLOT            Set the active slot.\n"
+            " oem [COMMAND...]           Execute OEM-specific command.\n"
+            "\n"
+            "boot image:\n"
+            " boot KERNEL [RAMDISK [SECOND]]\n"
+            "                            Download and boot kernel from RAM.\n"
+            " flash:raw PARTITION KERNEL [RAMDISK [SECOND]]\n"
+            "                            Create boot image and flash it.\n"
+            // TODO: give -c a long option, and remove the short options for this group?
+            " -c CMDLINE                 Override kernel command line.\n"
+            " --base ADDRESS             Set kernel base address (default: 0x10000000).\n"
+            " --kernel-offset            Set kernel offset (default: 0x00008000).\n"
+            " --ramdisk-offset           Set ramdisk offset (default: 0x01000000).\n"
+            " --tags-offset              Set tags offset (default: 0x00000100).\n"
+            " --page-size BYTES          Set flash page size (default: 2048).\n"
+            " --header-version VERSION   Set boot image header version.\n"
+            "\n"
+            // TODO: what device(s) used these? is there any documentation?
+            //" flashing unlock_bootloader REQUEST\n"
+            //"     unlock bootloader using request.\n"
+            //" flashing lock_bootloader\n"
+            //"     lock bootloader to prevent bootloader version rollback.\n"
+            //" continue                               Continue with autoboot.\n"
+            //"\n"
+            "Android Things:\n"
+            " stage IN_FILE              Sends given file to stage for the next command.\n"
+            " get_staged OUT_FILE        Writes data staged by the last command to a file.\n"
             "\n"
             "options:\n"
-            "  -w                                       Erase userdata and cache (and format\n"
-            "                                           if supported by partition type).\n"
-            "  -u                                       Do not erase partition before\n"
-            "                                           formatting.\n"
-            "  -s <specific device>                     Specify a device. For USB, provide either\n"
-            "                                           a serial number or path to device port.\n"
-            "                                           For ethernet, provide an address in the\n"
-            "                                           form <protocol>:<hostname>[:port] where\n"
-            "                                           <protocol> is either tcp or udp.\n"
-            "  -c <cmdline>                             Override kernel commandline.\n"
-            "  -i <vendor id>                           Specify a custom USB vendor id.\n"
-            "  -b, --base <base_addr>                   Specify a custom kernel base\n"
-            "                                           address (default: 0x10000000).\n"
-            "  --kernel-offset                          Specify a custom kernel offset.\n"
-            "                                           (default: 0x00008000)\n"
-            "  --ramdisk-offset                         Specify a custom ramdisk offset.\n"
-            "                                           (default: 0x01000000)\n"
-            "  --tags-offset                            Specify a custom tags offset.\n"
-            "                                           (default: 0x00000100)\n"
-            "  -n, --page-size <page size>              Specify the nand page size\n"
-            "                                           (default: 2048).\n"
-            "  -S <size>[K|M|G]                         Automatically sparse files greater\n"
-            "                                           than 'size'. 0 to disable.\n"
-            "  --slot <slot>                            Specify slot name to be used if the\n"
-            "                                           device supports slots. All operations\n"
-            "                                           on partitions that support slots will\n"
-            "                                           be done on the slot specified.\n"
-            "                                           'all' can be given to refer to all slots.\n"
-            "                                           'other' can be given to refer to a\n"
-            "                                           non-current slot. If this flag is not\n"
-            "                                           used, slotted partitions will default\n"
-            "                                           to the current active slot.\n"
-            "  -a, --set-active[=<slot>]                Sets the active slot. If no slot is\n"
-            "                                           provided, this will default to the value\n"
-            "                                           given by --slot. If slots are not\n"
-            "                                           supported, this does nothing. This will\n"
-            "                                           run after all non-reboot commands.\n"
-            "  --skip-secondary                         Will not flash secondary slots when\n"
-            "                                           performing a flashall or update. This\n"
-            "                                           will preserve data on other slots.\n"
-            "  --skip-reboot                            Will not reboot the device when\n"
-            "                                           performing commands that normally\n"
-            "                                           trigger a reboot.\n"
-            "  --disable-verity                         Set the disable-verity flag in the\n"
-            "                                           the vbmeta image being flashed.\n"
-            "  --disable-verification                   Set the disable-verification flag in\n"
-            "                                           the vbmeta image being flashed.\n"
+            " -w                         Wipe userdata.\n"
+            " -u                         Do not erase partition first when formatting.\n"
+            " -s SERIAL                  Specify a USB device.\n"
+            " -s tcp|udp:HOST[:PORT]     Specify a network device.\n"
+            // TODO: remove -i?
+            " -i VENDOR_ID               Filter devices by USB vendor id.\n"
+            " -S SIZE[K|M|G]             Use sparse files above this limit (0 to disable).\n"
+            " --slot SLOT                Use SLOT; 'all' for both slots, 'other' for\n"
+            "                            non-current slot (default: current active slot).\n"
+            " --set-active[=SLOT]        Sets the active slot before rebooting.\n"
+            " --skip-secondary           Don't flash secondary slots in flashall/update.\n"
+            " --skip-reboot              Don't reboot device after flashing.\n"
+            " --disable-verity           Sets disable-verity when flashing vbmeta.\n"
+            " --disable-verification     Sets disable-verification when flashing vbmeta.\n"
 #if !defined(_WIN32)
-            "  --wipe-and-use-fbe                       On devices which support it,\n"
-            "                                           erase userdata and cache, and\n"
-            "                                           enable file-based encryption\n"
+            " --wipe-and-use-fbe         Enable file-based encryption, wiping userdata.\n"
 #endif
-            "  --unbuffered                             Do not buffer input or output.\n"
-            "  -v, --verbose                            Verbose output.\n"
-            "  --version                                Display version.\n"
-            "  --header-version                         Set boot image header version while\n"
-            "                                           using flash:raw and boot commands to \n"
-            "                                           to create a boot image.\n"
-            "  -h, --help                               show this message.\n"
+            // TODO: remove --unbuffered?
+            " --unbuffered               Don't buffer input or output.\n"
+            " --verbose, -v              Verbose output.\n"
+            " --version                  Display version.\n"
+            " --help, -h                 Show this message.\n"
         );
     // clang-format off
     return 0;
@@ -1834,7 +1799,6 @@
                                             args[0] == "unlock_critical" ||
                                             args[0] == "lock_critical" ||
                                             args[0] == "get_unlock_ability" ||
-                                            args[0] == "get_unlock_bootloader_nonce" ||
                                             args[0] == "lock_bootloader")) {
                 do_oem_command("flashing", &args);
             } else if (args.size() == 2 && args[0] == "unlock_bootloader") {