I was working with a Meles board (8GB variant) trying to get it to boot alpine’s RISC-V generic u-boot rootfs… So I’m interacting with the board completely over UART, and things are going OK. No luck booting the kernel yet, it seems to just hang right after u-boot starts it…
Well, I pulled the SD card to make some tweaks and keep trying, but when I put it back in… the Meles was nonresponsive.
Now it won’t respond in any way. It’s power consumption dropped from ~4w to ~1-2, the green light comes on with power but never the blue light or the ethernet anymore, it never shows anything on UART now, and it doesn’t show up as a T-HEAD gadget on my computer if I hold the download button and plug in USB-C. It seems completely non-functional.
Is there anything I can do? Or is this board just bricked somehow? =(
it seems to just hang right after u-boot starts it…
I don’t think Alpine has TH1520 support. I just took a look at their generic U-Boot tarball and seems there’s only U-Boot binaries for U74 based boards, e.g. JH7110 and FU740.
it doesn’t show up as a T-HEAD gadget on my computer if I hold the download button and plug in USB-C
So there’s no UART output at all even in BROM mode (holding down the boot button)?
Normally when you’re holding down the download button and connect USB to your PC, on UART serial you should immediately see this:
Since BROM is, well BROM, baked inside the chip, if even BROM isn’t working (which shouldn’t happen), this might unfortunately indicate a hardware failure…
I suggest you contact Milk-V / customer support (depends on where you bought it, Arace I guess).
And by the way, for Meles (HW rev v1.3), with a fan in BROM mode it should consume around ~2W of power. Just tested it with a USB-C current meter.
Sure, but that’s never stopped me before. Usually the kernel can be convinced to work as long as you scrounge up a device tree. But I prefer to build my own kernels anyways.
From there, I’ll figure out userspace as I go.
Yeah… nothing on UART at all. sigh unfortunate.
Mine’s a v1.2… it’s been sitting on the bench a while, and I’m just now getting around to working on it. I’m not certain how accurate my power measurement is; usually I use 12v loads, and everything is on battery/solar, so 5v loads go through a buck converter, and sadly, my usual power meters won’t run on 5v, so I’m measuring upstream of the converter meaning the reading might be a bit high. I really should get more of those snazzy power measuring USB-C cables… but I digress.
Do I need to be running a fan on this thing? It didn’t come with one, but I did notice while it was working this was running run way hotter than my Mars board. Probably ought to pick some up somewhere… Will they accept any fan made for a pi?
You definitely should, since TH1520 can easily reach 70~80°C+ under full load (without any cooling) and it doesn’t have an IHS like the JH7110. This alone shouldn’t kill itself though since the chip can do thermal throttling to protect itself from that. Can’t say for sure but you sure don’t want it overheating anyway.
As for the fan, there’s a fan socket on the board and any PH2.0 header 5V fan should work. Just make sure the 5V/GND pins are correct.
For me here in China I can easily order coolers with that header (fan+heatsink combo) from taobao, but if it’s harder for you to buy then any heatsink that fits the SoC die with a fan on top should be fine. Never really used a Raspberry Pi and not sure what they use.
And in case you have a fan with XH2.54 header: there are GPIO pins for you to plug into. No PWM fan control this way however.
I’ve got some 5V fans sitting around so I figured I’d make the cooler myself. Why buy what you can make, right? The only tricky part is the connector, but you so kindly provided the spec PH2.0, so I thought it’d be simple enough. I had some old ones lying around that I thought would match, but they’re too big. So I ordered a kit of JST PH2.0 from DFROBOT (because why only have one?? This will come up again, to be sure)… and they’re the same as what I had before.
I don’t think the fan socket is PH2.0 =( Guess I’ll go off of GPIO until I can find the right connector.
I used a gauge pin to guess the pin pitch as 1.5mm, so I got some JST ZH connectors… those have the right pitch, but still don’t fit the header. I sanded it down some and jammed it in there, though, and now it works. xD
Usually the kernel can be convinced to work as long as you scrounge up a device tree. But I prefer to build my own kernels anyways.
I’m not certain how accurate my power measurement is; usually I use 12v loads, and everything is on battery/solar, so 5v loads go through a buck converter, and sadly, my usual power meters won’t run on 5v, so I’m measuring upstream of the converter meaning the reading might be a bit high. I really should get more of those snazzy power measuring USB-C cables… but I digress.