HappyModel EP2 Rx flashing problems | ExpressLRS Community | Page 1

fringe shale Jan 2, 2023, 9:42 PM

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Hello, I recently received a happymodel EP2 Rx for a quad, and I am having trouble flashing the rx. I originally flashed the rx with 3.1.2 firmware using Betaflight Passthrough, and it was successful. But when I went to bind it to my tx, using the same bind phrase and even putting the tx module into bind mode, the rx and tx module did not pair. I tried flashing it in bootloader mode, but it was unsuccessful. I realized 1.)I did not flash the rx to 2.5.1 and then to 3.1.2 and 2.) The rx will not go into wifi mode, it just blinks like it is searching for a tx. Any suggestions to get it working? Thanks

lone minnow Jan 2, 2023, 9:48 PM

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fringe shale Hello, I recently received a happymodel EP2 Rx for a quad, and I am having troub...

hi, we're missing a couple crucial pieces of information, like: what transmitter are you using? also, what version of elrs is flashed to the transmitter?

fringe shale Jan 2, 2023, 10:06 PM

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Sorry, 3.1.2 is flashed to the transmitter module, happymodel EStx24, which is in a tx16s

lone minnow Jan 2, 2023, 10:08 PM

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did you flash them with the same bind phrase?

fringe shale Jan 2, 2023, 10:09 PM

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Ya

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I made sure of it

lone minnow Jan 2, 2023, 10:09 PM

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so generally, putting the TX in bind mode if you already have a bind phrase flashed, won't help anything, but rather make it not work.

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next thing, if you are 100% sure that both RX and TX are on the same version with the same bind phrase (sounds like you are) then they should always just connect as long as they are the same frequency (2.4ghz for both of yours so not a problem either)

fringe shale Jan 2, 2023, 10:11 PM

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I believe the rx has a problem. The fact that the rx doesn't go into wifi mode, at all, confuses me

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and it is always unsuccessful when I tried to reflash firmware to be sure of any mistake I could've made

lone minnow Jan 2, 2023, 10:12 PM

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if the RX doesn't go into wifi mode that could be due to a couple of issues, including (but not limited to):

bad flash (aka soft locked / "bricked")
stupidly high wifi timeout
bootlooping receiver due to the uart being pulled high by the flight computer

lone minnow Jan 2, 2023, 10:13 PM

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fringe shale and it is always unsuccessful when I tried to reflash firmware to be sure of any...

what error did it give you?

fringe shale Jan 2, 2023, 10:13 PM

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Umm, let me get it

fringe shale Jan 2, 2023, 10:14 PM

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lone minnow if the RX doesn't go into wifi mode that could be due to a couple of issues, inc...

Btw, I know it is not a high wifi timeout and a bootloop. I set the wifi timeout to 30 seconds and the light isn't solid when I turn it on which, I believe to be, not in bootloader mode

lone minnow Jan 2, 2023, 10:15 PM

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well then it may be that the flash has gone bad for whatever reason

fringe shale Jan 2, 2023, 10:17 PM

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Here is the error

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I also made the solder joints were good

lone minnow Jan 2, 2023, 10:21 PM

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fringe shale Here is the error

could you please upload the whole log file for that flash from the configurator?

fringe shale Jan 2, 2023, 10:21 PM

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Ya

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📎 ExpressLRSBuildLog_20230102222119990.txt

lone minnow Jan 2, 2023, 10:21 PM

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also, just to double check, could you please upload a photo of your receiver, your flight computer, the wiring in between, and your receiver antenna?

fringe shale Jan 2, 2023, 10:22 PM

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👍

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📎 IMG_1099.HEIC 📎 IMG_1098.HEIC

lone minnow Jan 2, 2023, 10:25 PM

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fringe shale

configurator log looks fine so far, but what version of configurator are you using?

fringe shale Jan 2, 2023, 10:25 PM

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1.5.5

lone minnow Jan 2, 2023, 10:25 PM

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fringe shale

oh god no one can open that apple format...

fringe shale Jan 2, 2023, 10:25 PM

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lol, umm what should I do

lone minnow Jan 2, 2023, 10:26 PM

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send me a jpeg/png/whatever

fringe shale Jan 2, 2023, 10:26 PM

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Alright

lone minnow Jan 2, 2023, 10:26 PM

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everything but heic

fringe shale Jan 2, 2023, 10:27 PM

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Here ya go

lone minnow Jan 2, 2023, 10:34 PM

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fringe shale Here ya go

could you please describe EVERYTHING you do before you try to flash that receiver?

fringe shale Jan 2, 2023, 10:34 PM

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Like the process or what I have done before this

lone minnow Jan 2, 2023, 10:35 PM

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just tell me everything you did to try and flash that receiver

fringe shale Jan 2, 2023, 10:40 PM

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I used the configurator and flashed 3.1.2 to it successfully( I did not flash to 2.5.1 from factory and then to 3.2.1). When I tried to "pair" the tx module,estx24, with the rx, happymodel ep2, nothing happened. I thought it needed a power cycle, so I power cycled both the rx and the tx module- still nothing, I tried putting the tx module into bind mode to make sure I just didn't have the matching binding phrases-still no pair. Then, I thought, I might have the wrong firmware or something happened when flashing. When I went to flash the receiver through betaflight passthrough, everything was unsuccessful. I even tried flashing to 2.5.1 and then to 3.1.2 but no luck. I noticed throughout this that the receiver never ever went into wifi mode- other than turning it on for the first time when I originally flashed it.

lone minnow Jan 2, 2023, 10:41 PM

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could you make a quick 10 second film of the blinking on the receiver?

fringe shale Jan 2, 2023, 10:41 PM

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Ya

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lone minnow Jan 2, 2023, 10:50 PM

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fringe shale

yup that is a bad flash

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you see the led is constantly lit just very dim

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that always indicates a bad flash

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please do the steps as described here:

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!recovery

jaunty blazeBOT Jan 2, 2023, 10:51 PM

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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

fringe shale Jan 2, 2023, 10:55 PM

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I really appreciate the help!

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"Move the 5v wire going to the receiver to a 5V pad that only powers on when a LiPo is connected"
Quick question: I thought all pads on the fc were powered by usb
So how do I find a 5v pad only powered by lipos

lone minnow Jan 2, 2023, 10:59 PM

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fringe shale "Move the 5v wire going to the receiver to a 5V pad that only powers on when a L...

depends, usually there are some pads that are only powered by lipos

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if you have a pad that's labeled as 4V5, then your flight computer should also have 5V pads which should then only be powered by lipo

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another thing you can do if you do NOT have pads that powered only by lipo, is to not solder the 5V wire to the receiver

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well, solder one long wire, and cut it in the middle

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then expose a little bit of both ends

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so you can touch them together instead of plugging in the lipo

fringe shale Jan 2, 2023, 11:02 PM

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Gotcha

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Thanks

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So the lipo is just used to power the 5v pad not powered by usb

lone minnow Jan 2, 2023, 11:04 PM

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well the goal is basically just to power the receiver at a specific point in the flashing process

fringe shale Jan 2, 2023, 11:04 PM

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Oh ok

lone minnow Jan 2, 2023, 11:05 PM

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how you achieve that doesn't really matter

fringe shale Jan 2, 2023, 11:05 PM

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Gotcha

lone minnow Jan 2, 2023, 11:05 PM

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an easy way is to solder it to a pad that's only powered by lipo

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and then plug in the lipo at the right time

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another option is to just only connect the wire at the right time

fringe shale Jan 2, 2023, 11:05 PM

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Mhm, I don't have any 4v5 pads so I'll be doing that

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Do I have to flash to any specific firmware? Or can I flash to 3.1.2

lone minnow Jan 2, 2023, 11:15 PM

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just flash it to 3.1.2

fringe shale Jan 3, 2023, 10:03 PM

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lone minnow just flash it to 3.1.2

It worked! Thanks a ton!
Do you mind if I dm you a couple of questions about your career and expertise? I am really interested

lone minnow Jan 3, 2023, 10:16 PM

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fringe shale It worked! Thanks a ton! Do you mind if I dm you a couple of questions about you...

I can just tell you that in public lol

fringe shale Jan 3, 2023, 10:16 PM

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Alright!

lone minnow Jan 3, 2023, 10:16 PM

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I'm working as an IT specialist

fringe shale Jan 3, 2023, 10:16 PM

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How did you get into low level programming?

lone minnow Jan 3, 2023, 10:17 PM

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at some point seeing ben eaters 8 bit breadboard CPU

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then building it in minecraft

fringe shale Jan 3, 2023, 10:17 PM

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Oh wow lol

lone minnow Jan 3, 2023, 10:17 PM

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and then building other CPUs in minecraft

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and those you can only program in assembly / bare machine code

fringe shale Jan 3, 2023, 10:17 PM

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That's impressive

lone minnow Jan 3, 2023, 10:17 PM

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well, you usually know every instruction etc cause you designed it

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but yeah that's how I got into it

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and then I did some more stuff with arduino and others

fringe shale Jan 3, 2023, 10:18 PM

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Did you go to study in college?

lone minnow Jan 3, 2023, 10:19 PM

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fringe shale Did you go to study in college?

nope

fringe shale Jan 3, 2023, 10:20 PM

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And how did you get involved with elrs?

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Or are you just a helper

lone minnow Jan 3, 2023, 10:20 PM

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I always wanted to get into quads, for like 10 years or whatever

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but never really had the free time and money to do it

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and then I just did it anyway like a year and a half ago

fringe shale Jan 3, 2023, 10:21 PM

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Oh wow

lone minnow Jan 3, 2023, 10:22 PM

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started out flying flysky, then someone told me of expresslrs

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and I just joined the discord

fringe shale Jan 3, 2023, 10:22 PM

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Gotcha

lone minnow Jan 3, 2023, 10:22 PM

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and then I started watching the #help-and-support channel, and started helping some of the people myself

fringe shale Jan 3, 2023, 10:23 PM

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Im sure you learned a lot

lone minnow Jan 3, 2023, 10:23 PM

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I did, yes

fringe shale Jan 3, 2023, 10:23 PM

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Do you have any good sources for low level programming other than Ben Eater

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I want to learn about it

lone minnow Jan 3, 2023, 10:24 PM

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well I basically self-taught myself everything

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depending on what you wanna do, good sources usually are datasheets for the chips you wanna program, or specifications of the instruction set

fringe shale Jan 3, 2023, 10:25 PM

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Where did you start with such a complex subject

lone minnow Jan 3, 2023, 10:27 PM

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as I said, I just randomly got recommended ben eaters series

fringe shale Jan 3, 2023, 10:27 PM

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Mhm

lone minnow Jan 3, 2023, 10:27 PM

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and it just continued from there

#HappyModel EP2 Rx flashing problems