I heard from Xdevs23 that this command only works on macOS and Linux. It basically keeps encryption even after wiping internal storage. Normal command would be fastboot format userdata. Both wipe the internal storage, so pictures, videos, all stuff on sdcard
/* * The modifications performed to your device are * performed by yourself, thus you must perform the * leap of fate and accept the inevitable outcome, the * responsibilities of what to do with your device are passed to you. * * We are of no responsibility for any damages, data loss * or results of unexpected outcome, if you have **SERIOUS** * problems with this software, do not hesitate to contact * the developers or maintainers of your device port. * * We are not liable for anything that happens with your * device. Shall you somehow screw up and take the leap of faith * you may find that some companies may do indeed still honour * warranties, although we cannot give one ourselves. * * Don't be stupid and bet on that generosity of companies though, * please be responsible for what you do with your device. * Do not try overclocking up to glorious 1337 GHz thinking an OEM * would replace your glorious space heater only matched by the GTX480 etc. * * We recommend you to take the advice above regardless. */
* Please take a full [I]Nandroid[/I] backup! * Please copy your back up to an external device. * Back up your [I]Internal Storage[/I] * When completed, [I]clean flash[/I] the build (format using fastboot --wipe-and-use-fbe)
* Download the current version of XOS for your device. * Reboot into a compatible Android Recovery solution. (Note: We recommend [URL="https://forum.xda-developers.com/oneplus-5t/development/recovery-twrp-3-2-1-0-oreo-8-0-8-1-t3729673"]TWRP[/URL], use always the recommended version from first post) * Wipe [B]Wipe '/system' & '/cache', FORMAT /data preferably using fastboot --wipe-and-use-fbe (You will lose all your data incl. internal storage).[/B]. [I](For `Dirty Flash`, do not wipe anything)[/I] * Select the appropriate ROM zip and flash the current ROM build. * Want Google Apps? Obtain and flash the latest GApps from [url]http://opengapps.org/[/url] * Flash any other system modifications you may want * Reboot.
* Download the current version of XOS for your device. * Reboot into a compatible Android Recovery solution. (Note: We recommend TWRP) * [b]Please do not[/b] wipe anything, including Cache/Dalvik/ART, the ROM has you covered. * Select the appropriate ROM zip and flash the current ROM build. * Reflash any system modifications that do not survive updated (everything that is not addon.d-capable) * Reboot.