Upload Speed Limitation on MR33 with IPQ4019

[skylock]

WiFi Upload Capped at 23 Mbps on MR33 with OpenWrt 25.12.4

Setup: OpenWrt 25.12.4 | ath10k-ct | QCA9887 (phy0) + IPQ4019 (phy2) | VHT80 Ch.153 @ 20dBm

Performance:

• WiFi: ↓ 404.89 Mbps | ↑ 23.15 Mbps ⚠️
• Ethernet: ↓ 473 Mbps | ↑ 277.59 Mbps

Tested Optimizations:

• Mainline ath10k → unstable (WiFi drops)
• smallbuffers → -1.8%
• full-htt firmware → -15.3% DL
• TX Power 30dBm → self-interference (-50% DL)
• wpad-wolfssl → -9% UL
• Flow Offload → +4 Mbps UL, -111 Mbps DL (not viable)

Q: Is 23-24 Mbps WiFi upload a QCA9887 hardware limit, or am I missing something?

Thanks!

[skylock]

Investigation Update: Upload Speed Limitation on MR33 with IPQ4019

Setup

• Device: Meraki MR33
• Radio: IPQ4019 (2x2 embedded) - QCA9887 (1x1) disabled
• Channel: 153 (5.765 GHz, VHT80)
• TX Power: 20 dBm
• Testing: WiFi speedtest.net (same town server)

Complete Test Results Across Versions

OpenWrt Version	Download	Upload	Ping	Notes
v21.02.7 (r16847-f8282da11e)	316.34 Mbps	25.80 Mbps	6-14 ms	Best upload
v25.12.4 (r32933-4ccb782af7)	404.89 Mbps	23.15 Mbps	5-32 ms	Best download
v24.10.7 (r29197-ab4c7d6af7) @ Ch.153	360.60 Mbps	23.27 Mbps	6-11 ms	Channel optimized
v24.10.7 (r29197-ab4c7d6af7) @ Ch.36	321.24 Mbps	21.86 Mbps	6-11 ms	Default channel
v23.05.6 (r24232-539228933c)	420.07 Mbps	21.62 Mbps	6-34 ms	Highest download
v19.07.10 (r11427-9ce6aa9d8d)	310.69 Mbps	22.15 Mbps	7-12 ms	Stable

Key Observation

Upload consistently limited to 21.62 - 25.80 Mbps range across all OpenWrt versions, despite switching to IPQ4019 (2x2 MIMO).

Optimizations Tested (Minimal Impact)

• ✅ ath10k-ct driver (Candela)
• ✅ Different firmware variants (full-htt, standard)
• ✅ TX Power levels (20-30 dBm)
• ✅ Kernel buffer tuning (128MB rmem/wmem)
• ✅ Flow offloading modes
• ✅ Channel selection (36 vs 153)
• Result: None significantly improve upload beyond firmware version differences

Questions for MR33 Community

If you're running Meraki MR33 with OpenWrt, please share:

1. Your OpenWrt version: cat /etc/openwrt_release | grep VERSION
2. Which radio as primary AP? QCA9887 or IPQ4019?
3. Your WiFi speedtest results:
   • Download: ___ Mbps
   • Upload: ___ Mbps
   • Ping: ___ ms
4. Any special tuning you've applied?

Am I missing a configuration that unlocks higher upload speeds? 🤔