MediaTek Genio hardware design: what the EVK doesn't warn you about

Moving from the Genio EVK to a custom carrier board exposes issues that the reference documentation doesn’t flag clearly. Most of them are fast to explain and painful to discover on hardware. The ones below account for the majority of first-boot failures we see on custom Genio designs.

Key Insights

• Genio 520 and 720 have no HDMI — the only external display path is DisplayPort over Type-C (DPoC). Load display-dpoc.dtbo to enable it.
• SoC internal hardware names don’t match marketing names: Genio 510 (MT8370) uses MT8188 GPU/VPU/ISP internally. Yocto recipes must reference the internal name.
• GPIO75 is shared between SPI1 MOSI and WiFi 3.3V power enable on the EVK 40-pin header — enabling SPI1 cuts power to WiFi unless you remap the regulator to GPIO42 first.
• MT6390 is pin-compatible with MT6357 PMIC but has different power-on timing — sequences that work on MT6357 hang on MT6390, with a failure that looks like the SoC never leaving BL2.
• Genio 420, 520, and 720 share the same Yocto machine config and pin footprint — a Genio 720 design can bin down to Genio 520 for cost reduction without a PCB respin.

The HDMI assumption that kills carrier board schedules

Genio 520 and Genio 720 do not have HDMI output. This catches teams when they move from the devkit design to their own carrier board — or when they assume the Genio 720 EVK’s display setup matches what their product needs.

The only external display path on MT8391 (Genio 720), MT8371 (Genio 520), and MT8371LV (Genio 420) is DPoC — DisplayPort over Type-C. To enable it:

boot_conf=...#conf-display-dpoc.dtbo

This is not a BSP limitation or a missing driver — there’s no HDMI transmitter IP inside these SoCs. All three are pin-to-pin compatible (same VFBGA footprint) but none have HDMI.

MT8395 (Genio 1200) is a different package entirely (15x15mm vs the MT8391 footprint) and does have HDMI. It is not pin-compatible with MT8391 — a Genio 720 design cannot swap to Genio 1200 without a board respin.

The SoC internal name mapping trap

MediaTek’s hardware IP blocks use internal names that don’t match the marketing SoC names. This matters whenever you’re writing Yocto recipes that target specific silicon:

Marketing name	SoC ID	TFA Platform	GPU internal name	VPU/ISP internal name
Genio 350	mt8365	mt8365	mt8365	mt8365
Genio 360	mt8366	mt8366	mt8189	mt8366
Genio 420/520/720	mt8371lv/mt8371/mt8391	mt8391	mt8189	mt8189
Genio 510	mt8370	mt8188	mt8188	mt8188
Genio 700	mt8390	mt8188	mt8188	mt8188
Genio 1200	mt8395	mt8195	mt8195	mt8395

The practical consequence: Genio 510 (MT8370) uses MT8188 GPU, VPU, and ISP hardware. Any recipe that installs Mali GPU firmware or builds a camera daemon for Genio 510 must reference mt8188 internally, not mt8370. The BSP handles this automatically — but custom recipes that fail with a missing firmware error on Genio 510 are hitting this mapping issue.

Genio 360 (MT8366) uses mt8189 GPU and requires Mali GPU firmware (REQUIRE_FIRMWARE:mt8189 = "1"). If you’re porting Genio 350 bring-up experience to Genio 360 and GPU display isn’t coming up, this is often the cause — Genio 350 (mt8365) has no such requirement.

The SPI1 and WiFi power enable pin conflict on the EVK

The Genio 720 EVK exposes SPI1 on its 40-pin header. But GPIO75 is multiplexed between SPIM1_MO (SPI MOSI) and WCN_3V3_EN (WiFi module 3.3V power enable).

If your application needs SPI1 on the 40-pin header, you must remap the WiFi power enable from GPIO75 to GPIO42 first. Without this, enabling SPI1 cuts power to the WiFi module:

1. Change the pins_wcn_3v3_en fixed-regulator gpio from <&pio 75> to <&pio 42>
2. Update the pinctrl group to use PINMUX_GPIO42__FUNC_GPIO42
3. Add a gpio-hog node for GPIO42

This is EVK-specific. Custom carrier boards don’t inherit this conflict — they define their own pinmux from scratch.

PMIC timing: MT6390 vs MT6357

The Genio 720-class boards use MT6365 as the main PMIC (11 buck converters, 33 LDOs, 26MHz XO reference clock, 32kHz RTC). For GPU or custom power rails, an optional MT6691 auxiliary DC-DC provides additional I2C-programmable power.

MT6390 is pin-compatible with MT6357 and looks like a drop-in substitute. It’s not — they have different power-on timing. MT6390 regulators become ready earlier in the power-on sequence, and sequences written for MT6357 hang on MT6390. The failure mode looks like the SoC never getting past BL2.

If you’re substituting MT6390 on a design that was validated with MT6357, verify every timing assumption against the MT6390 datasheet before committing.

Genio 360 audio gotcha

Genio 510/700/520/720 use SOF (Sound Open Firmware) for the ARM DSP audio path. Genio 360 is different — in the current BSP, the SCP and SOF firmware are commented out in the SOC include:

# Temporarily removed:
#   linux-firmware-mt8188-scp
#   linux-firmware-mt8188-sof

Audio SOF is not functional on Genio 360 in the current public BSP. If your product requires audio on Genio 360, verify SOF status against the current BSP release before committing to that platform.

Three machines, one config — and what that means for custom boards

Genio 420 (MT8371LV), 520 (MT8371), and 720 (MT8391) all use the same Yocto machine configurations (genio-720-evk, etc.) and are pin-to-pin compatible. A design validated on Genio 720 hardware can be binned down to Genio 520 for cost reduction without a PCB respin — the Yocto machine config doesn’t change; the bootloader detects the chip ID at runtime.

The LPDDR tradeoff: Genio 520 supports LPDDR4X (up to 8GB at 4266 Mbps) in addition to LPDDR5, while Genio 720 requires LPDDR5X. If BOM cost matters and 16GB RAM isn’t required, Genio 520 with LPDDR4X can save meaningful cost without sacrificing NPU capability — the MDLA hardware is identical across all three.

We’ve brought up Genio 520, 700, 720, and 1200 on custom carrier boards at ProventusNova. The hardware design issues above account for the majority of first-boot failures we see.

Frequently Asked Questions

Does MediaTek Genio 720 have HDMI output?

No. Genio 520 and Genio 720 have no HDMI interface — only DisplayPort over Type-C (DPoC). Load display-dpoc.dtbo. This applies to MT8391, MT8371, and MT8371LV.

Why do recipes fail when building for Genio 510 in Yocto?

Genio 510 (MT8370) uses MT8188 GPU, VPU, and ISP hardware internally. Recipes must map mt8370 to mt8188 for firmware and daemon recipes. Same for Genio 700 (MT8390 uses mt8188).

Are Genio 520 and Genio 720 pin-compatible?

Yes. MT8391, MT8371, and MT8371LV share the same VFBGA footprint and Yocto machine configs. MT8395 (Genio 1200) uses a different package and is not pin-compatible.

Can I substitute MT6390 for MT6357 PMIC?

MT6390 is pin-compatible but has different power-on timing. Sequences that work with MT6357 hang with MT6390. Verify all power sequencing assumptions against the MT6390 datasheet.

What strapping resistors are required for Genio boot?

External 12 kΩ pull-up or pull-down resistors on all boot mode strapping pins. Boot mode is latched on RESETB rising edge. Floating pins produce random boot mode selection.