Is it possible to update or tweak the USB_A-to-HDMI adapter firmware to make it compatible with a Mac?

[maverick28]

I bought a USB 3.0 (USB-A) to HDMI adapter but was too late to notice it wouldn't work with Mac - Windows only; as such my Mac simply won't recognize my Sony TV. Unfortunately a return is not possible due to the damaged package, so I thought since there's the Device Firmware Update mode which is known to be used for modifying the behaviour of external devices and peripherals wouldn't it be possible to reprogram or change its firmware to make it compatible with a Mac? If yes, then how?

 

[joevt]

What adapter do you have? If it's DisplayLink then install the DisplayLink driver.

Why aren't you using a DisplayPort to HDMI adapter? It will have better performance than whatever you can get from USB 3.0.

Reverse engineering an undocumented firmware would take a very long time and/or lots of money.

 

[maverick28]

The adapter is Gembird. I have only 1 MiniDisplay port that I plug an external bootable SATA SSD in a Thunderbolt-controled enclosure in. To be able to connect an external monitor the only option is 2 USB-A ports. As for performance, I never came across information that the USB 3 performance with external displays is inferior compared to that of Thunderbolt. USB is just a universal bus and 5 Gb/s is more than enough for a crisp and clean picture. I don't use the TV set for production or gaming, anyway (if that matters).

 

[chrfr]

The adapter is Gembird. I have only 1 MiniDisplay port that I plug an external bootable SATA SSD in a Thunderbolt-controled enclosure in. To be able to connect an external monitor the only option is 2 USB-A ports. As for performance, I never came across information that the USB 3 performance with external displays is inferior compared to that of Thunderbolt. USB is just a universal bus and 5 Gb/s is more than enough for a crisp and clean picture. I don't use the TV set for production or gaming, anyway (if that matters).

I would switch things around. A SATA SSD doesn't benefit very much at all in performance when connected to Thunderbolt, but video will definitely perform better when connected directly to Mini DisplayPort as opposed to trying to get a USB adapter to work. The GPU isn't connected to USB so performance will always be worse that way than through one of the native display connections.

 

[maverick28]

I don't know but I clearly felt the difference at least on my old mid2012 MBP. With USB 3.0 I was noticing the OS would hiccup and struggle occasionally and not on par with the internal bootable SSD. No more with the cap removed. It runs less hot too. I'd prefer to give the running OS the best parts to avoid any disruptions and beachballing.
Also, doesn't the dedicated GPU kick in automatically in either scenario when an external display is connected? MiniDisplay is Thunderbolt which implies any Thunderbolt-compatible devices can be plugged in, it's not about TV monitors only anymore.

 

[Amethyst1]

As for performance, I never came across information that the USB 3 performance with external displays is inferior compared to that of Thunderbolt. USB is just a universal bus and 5 Gb/s is more than enough for a crisp and clean picture.

It doesn't work like that. You cannot connect a GPU to USB. You cannot connect a monitor or TV directly to USB either. Your adapter probably uses something like Displaylink that makes the CPU do all the work. Performance of these solutions is usually bad.

MiniDisplay is Thunderbolt which implies any Thunderbolt-compatible devices can be plugged in, it's not about TV monitors only anymore.

No. It's the other way around. Thunderbolt includes (Mini-)Displayport. You can connect a Displayport device to a Thunderbolt port, but a Thunderbolt device doesn't work when connected to Displayport.

 

[joevt]

USB 3.0 is 4 Gbps of data. Your adapter is 1920x1080x60Hzx24bpp = 2.99 Gbps so I suppose it could be lossless but usually there's some compression involved.

Anyway, since there's no macOS driver, your adapter will only work in Boot Camp. If you really want to use video from USB, then you should try a DisplayLink adapter which does have macOS drivers.
https://www.displaylink.com

To connect your Thunderbolt SSD and a display to your MacBook Pro (which only has one Thunderbolt 1 port), you should connect a Thunderbolt 3 dock using an Apple Thunderbolt 3 to Thunderbolt 2 adapter and a Thunderbolt 2 cable. A Thunderbolt 4 dock/hub is not an option unless you can get Big Sur installed. You could try a Thunderbolt 2 dock so that you don't need a second Thunderbolt 3 to Thunderbolt adapter to connect your Thunderbolt SSD enclosure but a Thunderbolt 3 dock has more features and is more future proof for when you decide to upgrade the Mac.

Which Thunderbolt SSD enclosure do you have?
There are some Thunderbolt 3 SSD enclosures that include a DisplayPort output and/or a second Thunderbolt port which can connect a DisplayPort display/adapter. So you wouldn't need a dock.

A Thunderbolt 3 dock or enclosure can add USB 3.1 gen 2 support (10 Gbps), so you could try a USB 10 Gbps to NVMe enclosure which are more portable and faster than a 2.5" SSD enclosure. I'm not sure it will be bootable from a Thunderbolt 1 Mac unless it's connected to a USB 3.0 port?

Thunderbolt 1 is limited to 10 Gbps but it has two channels so it basically has the same bandwidth as Thunderbolt 2 except the channels cannot be combined like they are in Thunderbolt 2/3/4. I am hoping that the display will use one channel and the SSD will use the other channel. I suppose you can verify this by testing the bandwidth of the SSD (if the SSD can use high enough bandwidth to be affected by the bandwidth used by the display).

What display are you connecting? A 1080p display only requires 3 Gbps, and your SSD is probably only 6 Gbps (4.8 Gbps of data), so they can both fit inside a single Thunderbolt 1 channel. So this is not a good test of multi channel functionality. A better test would be a 2560x1600 60Hz display (6 Gbps) (or 4K 30Hz display if you can somehow enable that resolution) and a USB to NVMe enclosure (10 Gbps). A display connected via Thunderbolt mostly only affects write speed so even if only one Thunderbolt channel was being used, the SSD would still have full read performance.