Hi,

1. What software do you use for speed measurement? It is recommended that you use speedtest.

2. You said that after you upgrade the firmware, the macbook only gets 54Mbps link speed, you can use other devices to have a test? Different devices may be have different result.

3.  How do you charge the EAP? EAP330 should be supported by 802.3at. If you charge it by 802.3af, it may affect the wireless speed.

4. Delete the SSID and config them again, becasue may be there is something wrong when you upgrade the firmware, you can delete them and then config them again to have a try.

5. May be you can have a factory reset for the EAP, and then check if the problem still exsits.

25mbps is not normal at a  5Ghz band.

check these settings:

If you are using a controller:

1. disable airtime fairness

2. disable rate limit

3. enable 11ac mode

4. enable wmm (QoS) in advanced wireless settings

5. In the AP list, click the AP menu, navigate to wireless settings --> radio transmission power, ensure the highest Tx power is selected in both 2.4G and 5Ghz.

6. use wi-fi analyzer on your phone, check which 5Ghz channel has the lowest interference, then set that EAP to that channel.

If you are using the EAP as a standalone AP without any controller:

1. backup your config first

2. reset the EAP into factory default via web UI or hardware reset.

3. After reset, you will see the default TP-Link EAPXXXXXX_5GHz SSID, connect your macbook to this 5G SSID, do speedtest again. See if it make any difference. If the result goes normal, then at least we know the low speed can be related to inappropriate configuration which might be triggered by the fw upgrade.