This is usually a corrupted OTA cache. Go to Settings > Apps > Show system > Google Services Framework > Clear data and cache. Then reboot and try again. If that fails, use LRSA to flash the full ROM.
If you follow instructions exactly (use the correct TWRP for TB-X704F, not a generic one), the risk is low. “Soft bricks” (boot loops) are fixable by re-flashing stock with LRSA. A true “hard brick” is rare unless you flash a bootloader from a different device. Lenovo Tb-x704f Android Update
| ROM | Android Version | Stability | Recommended For | | --- | --- | --- | --- | | LineageOS 18.1 | Android 11 | Very Stable | Daily driver, apps, media | | LineageOS 19.1 | Android 12L | Stable | Better tablet UI, split-screen | | LineageOS 20 | Android 13 | Beta (minor bugs) | Enthusiasts who want the latest | This is usually a corrupted OTA cache
The stock recovery partition on the TB-X704F only accepts Lenovo’s official signed updates. You need to replace this with . If that fails, use LRSA to flash the full ROM
Before you attempt any update outside of official channels, you must understand the risks:
For Lenovo, the return on investment for updating a three or four-year-old budget tablet simply didn't make financial sense. This is the reality of the Android ecosystem: unless you buy a flagship device or a Samsung tablet with a defined update promise, software longevity is not guaranteed.
The TB-X704F is the Wi-Fi only variant of the Lenovo Tab 4 8 (2017 release). The LTE variant is TB-X704L.