[Solved] Cannot update MMDVM_HS HAT on a JSTVRO Duplex Hotspot

[dl9sec]

Hi,

I recently bought this guy at "Jeff's General Store":




It's a JSTVRO MMDVM Duplex Hotspot. Really nice and tiny.

It has a Raspberry Pi Zero W with a "STM32-DVM / MMDVM_HS – Raspberry Pi Hat (GPIO)" MMDVM_HS_Dual_Hat piggybacked.
All setup went fine so far. The MMDVM_HS firmware 1.4.17 was delivered on the modem.

After a 'rpi-rw' and update/upgrade of the Pi-Star stuff, I tried to update the modem firmware via Pi-Star with

Code: Select all

sudo pistar-mmdvmhshatflash hs_dual_hat

which ends up in a

Code: Select all

:
Using Parser : Raw BINARY                                                            
Interface serial_posix: 57600 8E1                                                    
Failed to init device.
:

It took me several days to investigate the reason for that.
Finally I found out, that there is obviously a design incompatibility at the MMDVM_HS Hat:
The connection between pin 40 of the RPi Zero W connector to pin 7 of the STM32 (NRST) is missing. With appropriate tools (microscope, fine soldering iron, ...) the missing connection can be wired.
Then a connection between pin 4 (to STM32 BOOT1/PB2 via 10k) and pin 6 (GND) of the unpopulated 6-pin header footprint must be made. As far as I see, this connection can stay like in other MMDVM_HS designs after programming.

With these modifications it was possible to update the MMDVM_HS_Dual_Hat from 1.4.17 to 1.5.2.

Hope this helps...

73, Thorsten

[G8SEZ]

It looks like this is a modified clone of the design from here:

https://github.com/phl0/MMDVM_HS_Dual_H ... /r2.0-mini

which has SMA RF connectors substituted and the OLED pads added on but for some reason is missing the programming connections to the RPi.

It's almost as if some people don't really know what they're making.

[dl9sec]

The device doesn't look crappy, wasn't that cheap and bought at Amazon.
To be honest, I couldn't find a list of the good and the bad guys.

Just want to let others know, how this modem can be flashed with the Pi-Star tools, without an extra toolchain...

73, Thorsten

[dl9sec]

Either way the board designer should be contacted so that he can update the design.

They will get feedback via Amazon...

[kb4tez]

seem to have a bricked on since the firmware update. was working fine till then. Now when I power it on, all the LED's flash as it starts it's boot sequence, green light is solid on the pi board, but on the dual hat board on top, just a green solid light, and a red blinking light. the screen doesn't display anything. tried all the usual suspects, SD card, power supply, and re-downloading the pi-star software. I can't even see the modem on the wifi either. any ideas ?
John
KB4TEZ