Pushing settings.json fails with "Read-only file system"

[digitarald]

Running --only-remotify while phone is restarting from flashing v180.

Appending to prefs.js:
 { 'devtools.debugger.forbid-certified-apps': false,
  'devtools.debugger.prompt-connection': false,
  'b2g.adb.timeout': 0,
  'layout.css.report_errors': false }
Appending to settings.json:
 { 'developer.menu.enabled': true,
  'ftu.manifestURL': null,
  'debugger.remote-mode': 'adb-devtools',
  'devtools.debugger.remote-enabled': true,
  'screen.timeout': 600,
  'lockscreen.locked': false,
  'lockscreen.enabled': false }
{ [Error: Command failed: /bin/sh -c adb shell mount -o rw,remount /system && adb push /var/folders/_m/0hl2yq857n37js7nwtrv764w0000gq/T/flash-b2g114915-8923-1dah2jr/settings.json /system/b2g/defaults/settings.json && adb shell mount -o ro,remount /system
failed to copy '/var/folders/_m/0hl2yq857n37js7nwtrv764w0000gq/T/flash-b2g114915-8923-1dah2jr/settings.json' to '/system/b2g/defaults/settings.json': Read-only file system
]
  killed: false,
  code: 1,
  signal: null,
  cmd: '/bin/sh -c adb shell mount -o rw,remount /system && adb push /var/folders/_m/0hl2yq857n37js7nwtrv764w0000gq/T/flash-b2g114915-8923-1dah2jr/settings.json /system/b2g/defaults/settings.json && adb shell mount -o ro,remount /system' }

[digitarald]

Fabrice says that probably remount failed.

[digitarald]

Working on v18D, reopen if -r still fails for you