#Flashed wrong target on ELRS Rx and now nothing works.

69 messages · Page 1 of 1 (latest)

kind fern
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I recently got a DarwinFPV 129 with ELRS. Initially it told me to flash a BetaFPV target via WiFi. That didn’t work and it then said to use a DIY target. After trying that, the LED turn solid, like it is bound to my transmitter but it’s not. I now can’t get it into WiFi mode and I’ve tried using Betaflight passthrough with telemetry turned off. I’ve tried an FTDI adapter and that doesn’t work. With passthrough I get a com port error message in ExpressLRS configurator. The FTDI adapter error message says something like no serial data. I’ll try to post a couple pics of the receiver and the error messages. I’ve tried bridging two little pads as it doesn’t have a bootloader button. That doesn’t do anything either.

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sweet mortar
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You'll need to do a recovery flash. That pad below the antenna needs to be sorted to ground to put the receiver into bootloader mode. Follow this procedure, and use the BetaFPV Nano 2400 RX target

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!recovery

split gullBOT
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Follow these steps to recover a bricked RX:

- Move the 5v wire going to the receiver to a 5V pad that only powers on when a LiPo is connected 
- Disable Telemetry in Betaflight
- Save and Reboot
- Close Betaflight Configurator and unplug USB and LiPo
- Bridge the boot pads or hold down the boot button on the receiver
- Plug in USB
- Click "Build and Flash" in the ExpressLRS Configurator, selecting via Betaflight Passthrough method
- Wait for the line PASSTHROUGH DONE to appear
- Plug in LiPo (with boot button held down/bridged)
- Wait for the process to finish (with success hopefully)
- Unplug everything, unbridge the boot pads, then power on to confirm the LED blinks, and then goes into WiFi mode

Video Tutorial: https://www.youtube.com/watch?v=jYLwaWBkM_A

YouTube
DeltaGeek
How to Recover a Bricked ExpressLRS Receiver

https://www.expresslrs.org/2.0/quick-start/unbricking/

▶ Play video
kind fern
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I tried the procedure exactly as it was described. I get the message that says, “Could not open Com3, the port doesn’t exist”. I’m wondering if the error is in my computer USB port? I’ve tried to download the Silicon Labs drivers but I’m not computer savvy enough to know how to get it to install the driver.

sweet mortar
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Run the installer called VCP_V1.5.0_Setup_W7_x64_64bits

kind fern
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Thank V-22 for the link. I downloaded the driver and it installed nicely. I’m at work and will try it again when I get home tonight. I have a question for ya though. Does it matter if the FC is connected to Betaflight while building and flashing via ExpressLRS configurator? I guess I’m trying to understand how the passthrough process works. Is it BF that is sending the target to the receiver via the FC or is ExpressLRS configurator doing it? Can ExpressLRS talk to the FC or is it only Betaflight, INAV, and Ardupilot?

sweet mortar
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Betaflight must be closed to flash via Passthrough

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ELRS Configurator talks to the FC and puts it into serial Passthrough mode to flash the receiver

kind fern
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Still no luck. At least it’s not giving me a COM3 error anymore after downloading the ST drivers you sent the link for. I have the receiver wired to the FC with only the Tx and Rx wires. The 5v and ground are wired to a BEC so I can power it on after it says “Passthrough Done” and “Reset to Bootloader”. I’ve tried a couple ways to put it into bootloader mode. One I soldered a jumper from ground to the bare pad by the antenna connection. That didn’t do anything. Next I tried bridging two little pads that I saw on another forum were the boot pads but the result is the same, nothing.

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sweet mortar
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Connect a ground to the FC as well

kind fern
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Hmm, I still can’t figure this poor thing out. I connected to a common ground on the FC. It’s now saying “Failed to connect to ESP8266: no serial data received” Earlier in the log, right after it says Reset to bootloader, it says “Cannot detect RX target, blindly flashing!”

sweet mortar
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Can you post the full log and a clear photo of your wiring?

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!log

split gullBOT
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See the following image to save a log file from the configurator

kind fern
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Hope this shows the wiring clearly enough. Also I included pics of the configurator setup, just in case I missed something there??

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The little white wire is just what I’m using to bridge the two small pads that I was told were the boot pads.

sweet mortar
kind fern
sweet mortar
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But I would recommend using a different UART instead

kind fern
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It looks like maybe UART 4 is free. Should I try that? Would I need to do anything with the jumper on the FC?

sweet mortar
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What does the LED on the receiver do when you plug in USB?

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You should be using the BetaFPV Nano 2400 RX target for this receiver

kind fern
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When the receiver is wired to the FC completely, as in it’s getting its power from the FC, the LED instantly goes solid blue. It also goes solid blue as soon as it gets power from a stand alone power source, such as the BEC.

sweet mortar
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Based on the flashing log you'll need to do a recovery flash also.

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Get rid of the BEC. Connect the 5v wire on the receiver to a pad labeled 5v on the FC. Connect the boot pad to ground. Plug in USB, select build and flash in ELRS Configurator, with the BetaFPV Nano 2400 RX target. When PASSTHROUG DONE appears in ELRS Configurator, plug in your lipo. The LED on the receiver should light up solid.

kind fern
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Which is the correct jumper for the receiver? I’ve been told two different ones. I’m not sure if it’s the one pad near the antenna connector that I jump to ground or if I’m supposed to bridge the two tiny pads that are near the one pad I just mentioned.

sweet mortar
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The one pad near the antenna connector

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As far as I can tell from the non-existent documentation for this knock-off of a knock-off receiver 🙂

kind fern
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Well, I wired it to a 5v on the FC. The led on the receiver didn’t turn on when the FC was connected to usb, so that part is good. When I build and flash then get to passthrough done, I connect the LiPo and the receiver led turns solid blue but it still fails. Says it failed to connect to ESP8266 no serial data received. This is all for not most likely since I have a new receiver arriving tomorrow that I’m going to use instead of this one. Seems no matter what I try I can’t get this thing to work. Speaking of work, I gotta go back in so I’ll have to mess with it late tonight or tomorrow.

sweet mortar
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Next step would be moving the receiver to a different UART and trying the recovery flash again, or get a FTDI adapter and flash with that

kind fern
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I have an FTDI adapter and it still doesn’t work with that either. Weird deal.

sweet mortar
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You don't need the boot pad bridged for FTDI flashing

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Can you show how you had that wired?

kind fern
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Yeah, I’ll have to do that when I get back home. I wasn’t using a boot pad when trying the FTDI.

kind fern
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Here’s how the adapter is wired to the Rx. I made sure Tx goes to Rx and vice versa. I still get the same no serial data received fail message. I’m not going to mess with this cheap receiver anymore. The new one should be here today so I’ll wire that one up. If anyone wants me to ship this receiver to them so they can try to sort it out, I’d be happy to.

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sweet mortar
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Can you post the flash log?

kind fern
sweet mortar
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Try shortening your wires and checking your solder joints

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You could also try the pogo pins the FTDI came with

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Or put the RX into bootloader mode before flashing

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You didn't have a TX on when trying to flash, did you?

kind fern
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Yeah, it has says there is noise on every failure. No transmitter was on. Maybe my home WiFI network could be causing noise? The solder joints are all good. I tried the pogo pins and still would get the same error message. I've tried both ways to get it into bootloader mode and that doesn't work either, whether I jump the one pad to ground or bridge the two tiny pads.

sweet mortar
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Could be a stray solder blob or cold solder joint on the receiver. Difficult to troubleshoot further without more work.

kind fern
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I looked it over really well and didn't see anything. My new Happymodel EP1 Rx just showed up. Which target would I use for that one in the ExpressLRS configurator?

sweet mortar
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HappyModel EP 2400 RX

kind fern
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should I flash it with 2.5.2 then reflash it to 3.0.0?

sweet mortar
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I would just flash to 3.2.0 directly via FTDI or Passthrough

kind fern
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OK, I'm a little confused to whether I do or do not need to bridge the bootpad on this one for passthrough?

sweet mortar
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You do not

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That's only required when doing a recovery flash

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If the receiver is working normally, as it should fresh out of the package, it will respond to ELRS Configurator and reboot into bootloader by itself

kind fern
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OK, I just plugged in the USB and the LED is flashing green on the Rx. it was slowly flashing and now is quickly flashing, so it's in WiFi mode. Is it still ok to flash via passthrough now? I don't want to mess this one up, haha.

sweet mortar
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Yes

kind fern
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It's saying model mismatch on my Tx. I wonder if the binding phrase is case sensitive? I may have entered the wrong binding phrase then. Should I reflash it with what I think is the correct phrase?

sweet mortar
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Just turn model match on and off again in the ELRS lua

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Some manufacturers have been erroneously shipping receivers flashed with a model ID of 0, which enables model match

kind fern
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I can actually see the inputs moving under the receiver tab on BF. Everything look ok on the LUA screen? I really appreciate all your patience and help!

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sweet mortar
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Turn model match off again unless you need it

kind fern
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I don't even know what it does, haha.

sweet mortar