According to Choimobile.com and Vegaviet.com, there are a few solutions for this, and some users reported that they were successful. So you can try them for yourself
Solution #1 (Simple, recommended)
Download this file, reboot your device to fastboot mode (hold Volume UP + Volume DOWN + Power, then navigate to fastboot, press power to choose), then run fix_A890_recovery_stuck.bat
Solution #2
Flash stock recovery 3e via Teamwin . Copy the recovery below to your external SD card, flash the recovery below in TWRP
Recovery 3e forA890:
- S : https://app.box.com/s/wdlse0nhnsarhd0it9sk
- L : https://app.box.com/s/xi4ln0gh5qktbcu5e5pa
- K : https://app.box.com/s/ufa25bn12znif2ayqxjp
Source: http://vegaviet.com/threads/309226/#ixzz3JEz2clF2
Keywords: SKY, Pantech, VEGA, A890S, A890K, A890L, fix, stuck, recovery, choimobile, vegaviet, fastboot, teamwin