[Wear OS Q&A, Help & Troubleshooting] TCL7070x:
Of course, i can:

Here is the output from booting via fastboot with verbose mode ('.\fastboot.exe boot ..\..\..\rover_twrp.img --verbose'). Unfortunately no change between verbose and non-verbose mode:

Sending 'boot.img' (26682 KB) OKAY [ 0.843s]
Booting OKAY [ 11.621s]
Finished. Total time: 12.561s

and this is the output of all vars ('.\fastboot.exe getvar all'):

(bootloader) version:0.5
(bootloader) battery-soc-ok:yes
(bootloader) battery-voltage:3770009
(bootloader) variant:QRD eMMC
(bootloader) unlocked:yes
(bootloader) secure:no
(bootloader) version-baseband:
(bootloader) version-bootloader:rover-03.02.38.03.16
(bootloader) logical-block-size:0x200
(bootloader) erase-block-size:0x200
(bootloader) display-panel:
(bootloader) off-mode-charge:1
(bootloader) charger-screen-enabled:1
(bootloader) max-download-size: 0x1feffc00
(bootloader) partition-type:userdata:f2fs
(bootloader) partition-size:userdata: 0x12d0e8e00
(bootloader) partition-type:btlver:raw
(bootloader) partition-size:btlver: 0x400
(bootloader) partition-type:dpo:raw
(bootloader) partition-size:dpo: 0x2000
(bootloader) partition-type:msadp:raw
(bootloader) partition-size:msadp: 0x40000
(bootloader) partition-type:apdp:raw
(bootloader) partition-size:apdp: 0x40000
(bootloader) partition-type:mcfg:raw
(bootloader) partition-size:mcfg: 0x400000
(bootloader) partition-type:mdtpbak:raw
(bootloader) partition-size:mdtpbak: 0x2000000
(bootloader) partition-type:mdtp:raw
(bootloader) partition-size:mdtp: 0x2000000
(bootloader) partition-type:dip:raw
(bootloader) partition-size:dip: 0x100000
(bootloader) partition-type:limits:raw
(bootloader) partition-size:limits: 0x8000
(bootloader) partition-type:oem:raw
(bootloader) partition-size:oem: 0x1000000
(bootloader) partition-type:config:raw
(bootloader) partition-size:config: 0x8000
(bootloader) partition-type:keystore:raw
(bootloader) partition-size:keystore: 0x80000
(bootloader) partition-type:misc:raw
(bootloader) partition-size:misc: 0x100000
(bootloader) partition-type:persist:raw
(bootloader) partition-size:persist: 0x2000000
(bootloader) partition-type:cache:ext4
(bootloader) partition-size:cache: 0x4000000
(bootloader) partition-type:keymasterbak:raw
(bootloader) partition-size:keymasterbak: 0x100000
(bootloader) partition-type:keymaster:raw
(bootloader) partition-size:keymaster: 0x100000
(bootloader) partition-type:cmnlib64bak:raw
(bootloader) partition-size:cmnlib64bak: 0x100000
(bootloader) partition-type:cmnlib64:raw
(bootloader) partition-size:cmnlib64: 0x100000
(bootloader) partition-type:cmnlibbak:raw
(bootloader) partition-size:cmnlibbak: 0x100000
(bootloader) partition-type:cmnlib:raw
(bootloader) partition-size:cmnlib: 0x100000
(bootloader) partition-type:vendor:raw
(bootloader) partition-size:vendor: 0x20000000
(bootloader) partition-type:system:ext4
(bootloader) partition-size:system: 0x60000000
(bootloader) partition-type:devinfo:raw
(bootloader) partition-size:devinfo: 0x100000
(bootloader) partition-type:recovery:ext4
(bootloader) partition-size:recovery: 0x2000000
(bootloader) partition-type:boot:raw
(bootloader) partition-size:boot: 0x2000000
(bootloader) partition-type:vbmetabak:raw
(bootloader) partition-size:vbmetabak: 0x10000
(bootloader) partition-type:vbmeta:raw
(bootloader) partition-size:vbmeta: 0x10000
(bootloader) partition-type:dtbobak:raw
(bootloader) partition-size:dtbobak: 0x800000
(bootloader) partition-type:dtbo:raw
(bootloader) partition-size:dtbo: 0x800000
(bootloader) partition-type:abootbak:raw
(bootloader) partition-size:abootbak: 0x100000
(bootloader) partition-type:aboot:raw
(bootloader) partition-size:aboot: 0x100000
(bootloader) partition-type:splash:raw
(bootloader) partition-size:splash: 0xb00000
(bootloader) partition-type:sec:raw
(bootloader) partition-size:sec: 0x4000
(bootloader) partition-type:fsg:raw
(bootloader) partition-size:fsg: 0x180000
(bootloader) partition-type:DDR:raw
(bootloader) partition-size:DDR: 0x8000
(bootloader) partition-type:modemst2:raw
(bootloader) partition-size:modemst2: 0x180000
(bootloader) partition-type:modemst1:raw
(bootloader) partition-size:modemst1: 0x180000
(bootloader) partition-type:dspbak:raw
(bootloader) partition-size:dspbak: 0x1000000
(bootloader) partition-type:dsp:raw
(bootloader) partition-size:dsp: 0x1000000
(bootloader) partition-type:devcfgbak:raw
(bootloader) partition-size:devcfgbak: 0x40000
(bootloader) partition-type:devcfg:raw
(bootloader) partition-size:devcfg: 0x40000
(bootloader) partition-type:tzbak:raw
(bootloader) partition-size:tzbak: 0x200000
(bootloader) partition-type:tz:raw
(bootloader) partition-size:tz: 0x200000
(bootloader) partition-type:rpmbak:raw
(bootloader) partition-size:rpmbak: 0x80000
(bootloader) partition-type:rpm:raw
(bootloader) partition-size:rpm: 0x80000
(bootloader) partition-type:sbl1bak:raw
(bootloader) partition-size:sbl1bak: 0x80000
(bootloader) partition-type:sbl1:raw
(bootloader) partition-size:sbl1: 0x80000
(bootloader) partition-type:ssd:raw
(bootloader) partition-size:ssd: 0x2000
(bootloader) partition-type:fsc:raw
(bootloader) partition-size:fsc: 0x400
(bootloader) partition-type:modem:raw
(bootloader) partition-size:modem: 0x5400000
(bootloader) hw-revision:10000
(bootloader) serialno:<REDACTED>
(bootloader) kernel:lk
(bootloader) product:rover
all:
Finished. Total time: 0.350s

The behavior of the watch directly after trying to boot into the recovery:

It is looping through these stages:

* Logo -> Bootloader -> Logo ~8sec -> Vibration (Reboot) and black screen

(does not reach the TWRP screen at all)

Based on the video you sent me: I understand that vbmeta is a "mini os" that is responsible for verifying the other partitions, including the boot partition. If I understand correctly, vbmeta uses the key stored on the device in the keymaster partition (?)?

By flashing vbmeta with `.\fastboot.exe --disable-verity --disable-verification flash vbmeta vbmeta.img` this cryptographic verification is turned off, right?

All in all, it sounds like it's related to vbmeta blocking the boot process? Or I understand it completely wrong ;D

Anyway, thanks for going through this with me :giggle: