ℹ
info TP Link
Status LED blinks 3 times
The system is performing a firmware upgrade.
? What Causes This
Initiated by software update process.
ⓘ What This Means
Wait until the upgrade completes, which may take several minutes. Do not power off or reset during this time.
Source: page 43 of the official manual
From the manual
This error code appears in:
TP Link Re220 Range Extender