In 2020, I bought a NanoVNA V2 Plus4 from the official supplier (Tindie) - basically as a training exercise to learn how to use a VNA, so I'm not an expert and don't have a day job that needs it.

I played with it for a few months and then put it back in its box - without a battery inserted - until a few days ago when I wanted to check a 2.4GHz WiFi antenna (after 3 years! Clearly I'm a not a power user).

To my surprise when I plugged it into a USB port and powered it up it just showed the dreaded "white screen of death". I have not updated the firmware, but I believe a white screen is part of the firmware upgrade process and is normal when you press and hold the left jog button during power up. I notice a few other users reporting this symptom but that has not helped me "unbrick" my device - which seems to have bricked itself due to lack of use!

When I plug it into my Linux PC (I don't have Windows - I use Ubuntu Ubuntu 22.04.3 LTS) with the cable that came with the unit, it fails to enumerate as a USB device. I see this in dmesg:

kernel : usb 1-1.2 : new full-speed USB device number 91 using xhci_hcd
kernel : usb 1-1.2 : device descriptor read/64, error -32
kernel : usb 1-1.2 : device descriptor read/64, error -32
kernel : usb 1-1.2 : new full-speed USB device number 92 using xhci_hcd
kernel : usb 1-1.2 : device descriptor read/64, error -32
kernel : usb 1-1.2 : device descriptor read/64, error -32
kernel : usb 1-1-port2 : attempt power cycle
kernel : usb 1-1.2 : new full-speed USB device number 93 using xhci_hcd
kernel : usb 1-1.2 : Device not responding to setup address.
kernel : usb 1-1.2 : Device not responding to setup address.
kernel : usb 1-1.2 : device not accepting address 93, error -71
kernel : usb 1-1.2 : new full-speed USB device number 94 using xhci_hcd
kernel : usb 1-1.2 : Device not responding to setup address.
kernel : usb 1-1.2 : Device not responding to setup address.
kernel : usb 1-1.2 : device not accepting address 94, error -71
kernel : usb 1-1-port2 : unable to enumerate USB device

Some Googling hints that "error -32" may mean excessive current draw. I checked for shorts but the device appears ok. I tried different ports on my PC but get the same symptom on all ports.

Other weirdness is that it takes a long time to turn off - but that could be just charge remaining on the USB filter cap.

Also, if I remove then reinsert the battery, powering on does not cause the diagnostic LEDs to light and the display remains dark. The battery is known good (4.1 volts). But plugging the device into a USB port does cause the diagnostic LEDs to come on (1,2,3, flashing 4). I could not find in the user guide what the LEDs were supposed to indicate.

*I'm not expecting a magic solution to this - but I am curious, given that other users have experienced WSOD issues, as to whether after 3 years in the field this is now a known issue with a known solution?*

Cheers,
Andrew

Hi, can you try entering DFU mode by holding down the left button when powering on, and see if it shows up as a USB serial device?
If there is a delay when turning off, it likely means it's drawing very little current and this may be that the firmware is not running.
When removing and reinserting the battery, it is normal that the device will not power on until you plug in USB once to activate the battery management IC.
Thanks

Thank you for the prompt response and the info about battery mode. When I press and hold the left jog button and power on, dmesg shows:

Jan 07 17:15:07 apollo kernel: usb 1-1.2: new full-speed USB device number 111 using xhci_hcd
Jan 07 17:15:07 apollo kernel: usb 1-1.2: device descriptor read/64, error -32
Jan 07 17:15:07 apollo kernel: usb 1-1.2: device descriptor read/64, error -32
Jan 07 17:15:07 apollo kernel: usb 1-1.2: new full-speed USB device number 112 using xhci_hcd
Jan 07 17:15:08 apollo kernel: usb 1-1.2: device descriptor read/64, error -32
Jan 07 17:15:08 apollo kernel: usb 1-1.2: device descriptor read/64, error -32
Jan 07 17:15:08 apollo kernel: usb 1-1-port2: attempt power cycle
Jan 07 17:15:09 apollo kernel: usb 1-1.2: new full-speed USB device number 113 using xhci_hcd
Jan 07 17:15:09 apollo kernel: usb 1-1.2: Device not responding to setup address.
Jan 07 17:15:10 apollo kernel: usb 1-1.2: Device not responding to setup address.
Jan 07 17:15:10 apollo kernel: usb 1-1.2: device not accepting address 113, error -71
Jan 07 17:15:10 apollo kernel: usb 1-1.2: new full-speed USB device number 114 using xhci_hcd
Jan 07 17:15:10 apollo kernel: usb 1-1.2: Device not responding to setup address.
Jan 07 17:15:10 apollo kernel: usb 1-1.2: Device not responding to setup address.
Jan 07 17:15:10 apollo kernel: usb 1-1.2: device not accepting address 114, error -71
Jan 07 17:15:10 apollo kernel: usb 1-1-port2: unable to enumerate USB device

...and when I run the VNA_View-x86_64.AppImage program, the "Device" menu shows (grayed out) "No devices found; check dmesg or device manager"

Cheers

...also I see no /dev/tty devices:

~ ❯ ll /dev/tty
crw-rw-rw- 1 root tty 5, 0 Jan  7 10:52 /dev/tty

a very empty battery may pull a bit higher current as your usb port
maybe can give?? try to load the battery for a while (either on pc port
or with a smartphone charger) and try again

another option that causes a WSOD is if the display is moved outwards
(by some force while dangling around in your drawer) and a case edge is
pressing the touch sensor field .. that also causes the cpu to show a
white screen (try to fire the unit up without case) ... a slight press
on the display may cause exactly that same symptom

so ... at first reload battery ... next ... after loading battery try
again if unit now works ... still wsod?? then try without case ...

only from lying in the box there should be no problem (except deep
discharge of battery depending how long it was out of usage)

dg9bfc sigi

Am 07.01.2024 um 06:58 schrieb android:

>
> In 2020, I bought a NanoVNA V2 Plus4 from the official supplier
> (Tindie) - basically as a training exercise to learn how to use a VNA,
> so I'm not an expert and don't have a day job that needs it.
>
> I played with it for a few months and then put it back in its box -
> without a battery inserted - until a few days ago when I wanted to
> check a 2.4GHz WiFi antenna (after 3 years! Clearly I'm a not a power
> user).
>
> To my surprise when I plugged it into a USB port and powered it up it
> just showed the dreaded "white screen of death". I have not updated
> the firmware, but I believe a white screen is part of the firmware
> upgrade process and is normal when you press and hold the left jog
> button during power up. I notice a few other users reporting this
> symptom but that has not helped me "unbrick" my device - which seems
> to have bricked itself due to lack of use!
>
> When I plug it into my Linux PC (I don't have Windows - I use Ubuntu
> Ubuntu 22.04.3 LTS) with the cable that came with the unit, it fails
> to enumerate as a USB device. I see this in dmesg:
>
> kernel: usb 1-1.2: new full-speed USB device number 91 using xhci_hcd
> kernel: usb 1-1.2: device descriptor read/64, error -32
> kernel: usb 1-1.2: device descriptor read/64, error -32
> kernel: usb 1-1.2: new full-speed USB device number 92 using xhci_hcd
> kernel: usb 1-1.2: device descriptor read/64, error -32
> kernel: usb 1-1.2: device descriptor read/64, error -32
> kernel: usb 1-1-port2: attempt power cycle
> kernel: usb 1-1.2: new full-speed USB device number 93 using xhci_hcd
> kernel: usb 1-1.2: Device not responding to setup address.
> kernel: usb 1-1.2: Device not responding to setup address.
> kernel: usb 1-1.2: device not accepting address 93, error -71
> kernel: usb 1-1.2: new full-speed USB device number 94 using xhci_hcd
> kernel: usb 1-1.2: Device not responding to setup address.
> kernel: usb 1-1.2: Device not responding to setup address.
> kernel: usb 1-1.2: device not accepting address 94, error -71
> kernel: usb 1-1-port2: unable to enumerate USB device
>
> Some Googling hints that "error -32" may mean excessive current draw.
> I checked for shorts but the device appears ok. I tried different
> ports on my PC but get the same symptom on all ports.
>
> Other weirdness is that it takes a long time to turn off - but that
> could be just charge remaining on the USB filter cap.
>
> Also, if I remove then reinsert the battery, powering on does not
> cause the diagnostic LEDs to light and the display remains dark. The
> battery is known good (4.1 volts). But plugging the device into a USB
> port does cause the diagnostic LEDs to come on (1,2,3, flashing 4). I
> could not find in the user guide what the LEDs were supposed to indicate.
>
> *I'm not expecting a magic solution to this - but I am curious, given
> that other users have experienced WSOD issues, as to whether after 3
> years in the field this is now a known issue with a known solution?*
>
> Cheers,
> Andrew
>
>

Thanks Siegfried. I get the same usb errors reported on dmesg regardless of whether I have the battery inserted or not, and I even disconnected the display so I think that rules out a faulty display.

In summary,

1. I have the PCB out of the box, battery removed, display removed.

2. I plug it into my Linux desktop PC with the supplied USB cable.

3. The battery management chip lights LEDs (1, 2, 3, flashing 4) - but no USB enumeration is attempted.

4. I turn the power on and USB enumeration is attempted but fails with:

Jan 09 17:34:44 apollo kernel: usb 1-1.2: new full-speed USB device number 28 using xhci_hcd
Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
Jan 09 17:34:45 apollo kernel: usb 1-1.2: new full-speed USB device number 29 using xhci_hcd
Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
Jan 09 17:34:45 apollo kernel: usb 1-1-port2: attempt power cycle
Jan 09 17:34:47 apollo kernel: usb 1-1.2: new full-speed USB device number 30 using xhci_hcd
Jan 09 17:34:47 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
Jan 09 17:34:47 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
Jan 09 17:34:47 apollo kernel: *usb 1-1.2: device not accepting address 30, error -71*
Jan 09 17:34:48 apollo kernel: usb 1-1.2: new full-speed USB device number 31 using xhci_hcd
Jan 09 17:34:48 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
Jan 09 17:34:48 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
Jan 09 17:34:48 apollo kernel: *usb 1-1.2: device not accepting address 31, error -71*
Jan 09 17:34:48 apollo kernel: *usb 1-1-port2: unable to enumerate USB device*

5. Power off and power on with the left jog button pressed gives the same USB enumeration error as above.

I'll try it on a laptop and see if that makes any difference.

Android
This might seem facile but...
Have you tried another cable?

Dave, G1OGY


On Tue, 9 Jan 2024 at 12:58, android <androidarmstrong@gmail.com> wrote:

> Thanks Siegfried. I get the same usb errors reported on dmesg regardless
> of whether I have the battery inserted or not, and I even disconnected the
> display so I think that rules out a faulty display.
>
> In summary,
>
> 1. I have the PCB out of the box, battery removed, display removed.
>
> 2. I plug it into my Linux desktop PC with the supplied USB cable.
>
> 3. The battery management chip lights LEDs (1, 2, 3, flashing 4) - but no
> USB enumeration is attempted.
>
> 4. I turn the power on and USB enumeration is attempted but fails with:
>
> Jan 09 17:34:44 apollo kernel: usb 1-1.2: new full-speed USB device number 28 using xhci_hcd
> Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel: usb 1-1.2: new full-speed USB device number 29 using xhci_hcd
> Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel: *usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel: usb 1-1-port2: attempt power cycle
> Jan 09 17:34:47 apollo kernel: usb 1-1.2: new full-speed USB device number 30 using xhci_hcd
> Jan 09 17:34:47 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:47 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:47 apollo kernel: *usb 1-1.2: device not accepting address 30, error -71*
> Jan 09 17:34:48 apollo kernel: usb 1-1.2: new full-speed USB device number 31 using xhci_hcd
> Jan 09 17:34:48 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:48 apollo kernel: *usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:48 apollo kernel: *usb 1-1.2: device not accepting address 31, error -71*
> Jan 09 17:34:48 apollo kernel: *usb 1-1-port2: unable to enumerate USB device*
>
> 5. Power off and power on with the left jog button pressed gives the same
> USB enumeration error as above.
>
> I'll try it on a laptop and see if that makes any difference.
>
>
>
>
>
>
>

i am only aa windoze user so i can not say anything about your error ..
sorry

i use nanovna app with my saa2n and with nano vna 2plus4 ... to measure
things and to upgrade fw

so sorry that i can not be of better help

dg9bfc sigi

Am 09.01.2024 um 07:36 schrieb android:

>
> Thanks Siegfried. I get the same usb errors reported on dmesg
> regardless of whether I have the battery inserted or not, and I even
> disconnected the display so I think that rules out a faulty display.
>
> In summary,
>
> 1. I have the PCB out of the box, battery removed, display removed.
>
> 2. I plug it into my Linux desktop PC with the supplied USB cable.
>
> 3. The battery management chip lights LEDs (1, 2, 3, flashing 4) - but
> no USB enumeration is attempted.
>
> 4. I turn the power on and USB enumeration is attempted but fails with:
>
> Jan 09 17:34:44 apollo kernel: usb 1-1.2: new full-speed USB device number 28 using xhci_hcd
> Jan 09 17:34:45 apollo kernel:*usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel:*usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel: usb 1-1.2: new full-speed USB device number 29 using xhci_hcd
> Jan 09 17:34:45 apollo kernel:*usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel:*usb 1-1.2: device descriptor read/64, error -32*
> Jan 09 17:34:45 apollo kernel: usb 1-1-port2: attempt power cycle
> Jan 09 17:34:47 apollo kernel: usb 1-1.2: new full-speed USB device number 30 using xhci_hcd
> Jan 09 17:34:47 apollo kernel:*usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:47 apollo kernel:*usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:47 apollo kernel:*usb 1-1.2: device not accepting address 30, error -71*
> Jan 09 17:34:48 apollo kernel: usb 1-1.2: new full-speed USB device number 31 using xhci_hcd
> Jan 09 17:34:48 apollo kernel:*usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:48 apollo kernel:*usb 1-1.2: Device not responding to setup address.*
> Jan 09 17:34:48 apollo kernel:*usb 1-1.2: device not accepting address 31, error -71*
> Jan 09 17:34:48 apollo kernel:*usb 1-1-port2: unable to enumerate USB device*
>
> 5. Power off and power on with the left jog button pressed gives the
> same USB enumeration error as above.
>
> I'll try it on a laptop and see if that makes any difference.
>
>

Good point Dave. I tried a different cable but got the same error.

No worries Siegfried.

I'm going to check a few voltages and signals.
I'll go as far as replacing the MCU (since that has the USB support) but if that doesn't work I'll have to declare this horse dead even though I hardly rode it to the shops.

Cheers
Andrew

Thought that it might be worth mentioning, Andrew.

Just out of interest I have run some comparisons on my own kit.
FWIW here is my dmesg(1) O/P:

148.866401] usb 7-1: new full-speed USB device number 2 using uhci_hcd
[ 149.058448] usb 7-1: New USB device found, idVendor=04b4,
idProduct=0008, bcdDevice= 0.01
[ 149.058454] usb 7-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 149.058456] usb 7-1: Product: You just lost the game.
[ 149.058459] usb 7-1: Manufacturer: The game
[ 149.058461] usb 7-1: SerialNumber: You just lost the game.
[ 149.255706] cdc_acm 7-1:1.0: ttyACM0: USB ACM device
[ 149.257960] usbcore: registered new interface driver cdc_acm
[ 149.257962] cdc_acm: USB Abstract Control Model driver for USB
modems and ISDN adapters

Now, this machine is an older USB2/USB1 enabled box (as are most of my
linuxen) and is installed with Debian 11.8 [Bullseye].
(I get similar O/P from another machine of the same type installed
with Debian 12.4 [Bookworm].)
Neither box has USB3 ports and xhci_hcd is not present on the system.
All external ports connect to a "Linux Foundation 1.1 root hub".
You'll see that `uhci_hcd` is the driver - rather than the later and
USB3-enabled `xhci_hcd`.

lsusb(8) lists:
Bus 007 Device 003: ID 04b4:0008 Cypress Semiconductor Corp. You just
lost the game.
Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

The Device ID identifies a Cypress CDC ACM serial port

The only USB3-enabled machine I have to hand is a Windows10 box.
I'll try to boot it with a (Debian) `Live CD` to see if there are any
differences.

Does your machine have any specifically USB2 ports you can try? It
could make a difference...

Dave, G1OGY

On Wed, 10 Jan 2024 at 10:00, android <androidarmstrong@gmail.com> wrote:

>
> Good point Dave. I tried a different cable but got the same error.
>

Not so good news from the other machine. Booted from a fresh Debian
12.4 "Live CD"
The box is not at all new - but does have genuine USB3 (blue) ports.

user@debian:~$ lsusb
Bus 003 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 004: ID 0c45:6449 Microdia Laptop_Integrated_Webcam_E4HD
Bus 001 Device 003: ID 0bda:0129 Realtek Semiconductor Corp. RTS5129
Card Reader Controller
Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub
Bus 002 Device 004: ID 1221:3234 Unknown manufacturer Disk (Thumb
drive) >>> the USB stick this data was written to
Bus 002 Device 002: ID 090c:1000 Silicon Motion, Inc. - Taiwan
(formerly Feiya Technology Corp.) Flash Drive >>> The USB stick
with LiveCD
Bus 002 Device 005: ID 04b4:0008 Cypress Semiconductor Corp. CDC ACM
serial port >>> [ the nano VNA ]
Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
user@debian:~$

dmesg shows that xhci_hcd is loaded and correctly enumerates the
nanoVNA's Cypress device. But note (above) that it is attached,
internally, to a USB2 hub.

[ 1152.405883] usb 2-1: new full-speed USB device number 5 using xhci_hcd
[ 1152.555432] usb 2-1: New USB device found, idVendor=04b4,
idProduct=0008, bcdDevice= 0.01
[ 1152.555446] usb 2-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1152.555451] usb 2-1: Product: You just lost the game.
[ 1152.555454] usb 2-1: Manufacturer: The game
[ 1152.555457] usb 2-1: SerialNumber: You just lost the game.
[ 1152.634960] cdc_acm 2-1:1.0: ttyACM0: USB ACM device
[ 1152.634987] usbcore: registered new interface driver cdc_acm
[ 1152.634989] cdc_acm: USB Abstract Control Model driver for USB
modems and ISDN adapters
user@debian:~$


Given your nano was working when put away, other than trying it on a
Windows 10 box (don't pre-install "drivers", in the first instance),
I'm out of ideas.




Dave, G1OGY

On Wed, 10 Jan 2024 at 16:59, Dave (G1OGY) <g1ogy@g1ogy.com> wrote:

>
> Thought that it might be worth mentioning, Andrew.
>
> Just out of interest I have run some comparisons on my own kit.
> FWIW here is my dmesg(1) O/P:
>
> 148.866401] usb 7-1: new full-speed USB device number 2 using uhci_hcd
> [ 149.058448] usb 7-1: New USB device found, idVendor=04b4,
> idProduct=0008, bcdDevice= 0.01
> [ 149.058454] usb 7-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
> [ 149.058456] usb 7-1: Product: You just lost the game.
> [ 149.058459] usb 7-1: Manufacturer: The game
> [ 149.058461] usb 7-1: SerialNumber: You just lost the game.
> [ 149.255706] cdc_acm 7-1:1.0: ttyACM0: USB ACM device
> [ 149.257960] usbcore: registered new interface driver cdc_acm
> [ 149.257962] cdc_acm: USB Abstract Control Model driver for USB
> modems and ISDN adapters
>
> Now, this machine is an older USB2/USB1 enabled box (as are most of my
> linuxen) and is installed with Debian 11.8 [Bullseye].
> (I get similar O/P from another machine of the same type installed
> with Debian 12.4 [Bookworm].)
> Neither box has USB3 ports and xhci_hcd is not present on the system.
> All external ports connect to a "Linux Foundation 1.1 root hub".
> You'll see that `uhci_hcd` is the driver - rather than the later and
> USB3-enabled `xhci_hcd`.
>
> lsusb(8) lists:
> Bus 007 Device 003: ID 04b4:0008 Cypress Semiconductor Corp. You just
> lost the game.
> Bus 007 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
>
> The Device ID identifies a Cypress CDC ACM serial port
>
> The only USB3-enabled machine I have to hand is a Windows10 box.
> I'll try to boot it with a (Debian) `Live CD` to see if there are any
> differences.
>
> Does your machine have any specifically USB2 ports you can try? It
> could make a difference...
>
> Dave, G1OGY
>
> On Wed, 10 Jan 2024 at 10:00, android <androidarmstrong@gmail.com> wrote:
> >
> > Good point Dave. I tried a different cable but got the same error.
> >
>
>
>
>
>

Hi, it looks like there may be issues with the firmware being corrupted.
Can you message us through "Contact Seller" on Tindie with your order number, so we can send you a replacement main board?
Thanks

Thanks Dave
I appreciate the time you've put in to help me out. My ancient (2012 vintage) laptop only has USB2 and I get the same symptom on that.

Well thank you! I didn't expect such good after sales support - especially for an out of warranty device.
I've contacted the tindie store as requested.
Cheers
Andrew

Pleased to be of service.
73

Dave, G1OGY

On Fri, 12 Jan 2024 at 12:31, android <androidarmstrong@gmail.com> wrote:

>
> Thanks Dave
> I appreciate the time you've put in to help me out. My ancient (2012 vintage) laptop only has USB2 and I get the same symptom on that.
>

While I was waiting for the replacement main board to arrive, and since I didn't have anything to lose, I replaced the GD32F303CCT6 MCU with an STM32F303CCT7, then shorted the BOOT0 pin (pin 44) to VDD (pin 43) and it was enumerated by Linux OK:

>
>
>
> Jan 21 16:41:50 apollo kernel: usb 1-1.2: New USB device found,
> idVendor=0483, idProduct=df11, bcdDevice=22.00
> Jan 21 16:41:50 apollo kernel: usb 1-1.2: New USB device strings: Mfr=1,
> Product=2, SerialNumber=3
> Jan 21 16:41:50 apollo kernel: usb 1-1.2: Product: STM32  BOOTLOADER
> Jan 21 16:41:50 apollo kernel: usb 1-1.2: Manufacturer: STMicroelectronics
>
> Jan 21 16:41:50 apollo kernel: usb 1-1.2: SerialNumber: 205936632031
>
>

I guess I should put the old MCU back and repeat the exercise but at least I have made some progress. It would have been easier if the S301 was populated on the board so that I could force boot mode, but I couldn't even find the pads for that switch.

Cheers

Andrew