MinimOSD says "Update Charset" on bootup, must reset first

I have APM2, XBee Pro 900, connected to MinimOSD without TX line as advised.  When I power up the system, the MinimOSD always shows Booting, then "Update Charset" and goes no further.  If I press the hard reset it works fine again, but never on initial bootup.  It also does this if I unplug the XBee and connect the MinimOSD directly to the APM with all pins connected.

Is anyone else having this problem?  This does not seem like normal behavior.

I have also re-updated the firmware and charset with the MinimOSD software and nothing changed.

Please help!

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Looks like this was resolved today with a software update on the OSD!

Hey David, thanks for that :-)

if (mavlink_active == 0 && millis() < 20000 && millis() > 5000) {
if (c == '\n' || c == '\r') {
} else {
crlf_count = 0;
if (crlf_count == 3) {

Hi,have you already solved the problem? I met the same problem as yours. If you know how to finish it ,can you help me?Thanks!

I'm seeing this issue again after upgrading to the latest minimOSD firmware (2.0) with APM 2 using 2.8.1.  Is there a good way to correct this that doesn't require code tweaking?

It seems terrible that the standard procedure after powering up is to hard reset the OSD before it is actually usable.

I've added Issue 32 to the minimOSD project for this:

Hopefully a good solution can be found and included in the code base.

OK, in the latest MinimOSD release, you can avoid the "Charset Update" problem on power/boot by simply setting the TELEM_DELAY to be 4 seconds or less.  Setting it to 5 seconds or more will cause it every time.  Enjoy!

Checking to see if there is an update to this one. Slightly annoying to get to my OSD to reset it.

hi all, 

I have a problem, 

after updating the firmware with the latest relase and subsequently updated the character set with Latest_Charset.mcm

but always visualize these writings:

can anyone help me? please

I am having this issue UPDATE CHARSET
PX4 2.76 plane
OSD fw 2.0

I have tried various TELEM_DELAY as recommended (default was 0) at no avail.
Initially the two supply jumpers on the minimOSD was connected (supplying from 12V).
I removed the solder jumpers and problem persists.

Would this not justify a OSD firmware fix?!
It is quite frustrating...
/ Tom

I have now arrived at the conclusion that the PX4 needs longer time than the APM to boot and get going with Mavlink hartbeat transmission. More than the 5 seconds the minimOSD is programmed to wait for. Therefore even TELEM_DELAY at 0 will not do the trick.

I figured out one workaroud and one fix to this problem.

Workaround: Connect a RC (resistor-capacitance) time constant over the OSD reset button. Very simple and works fine. It´s like pressing the RESET button for the first seconds of power up, thus providing more time for the PX4 to wake up and deliver the Mavlink heartbeats. Though it´s less satisfying to apply a hardware workaround to a software problem.

Fix: Increasing the minimOSD time constant from 5 seconds by hacking the firmware (thanks Gabor for identifying the relevant code). I will attempt this, although my mind was set for Plug and Play, not hack and compile to manage this project :/


(I still suggest an official firware update to solve the issue. Very reasonable since this problem will most likely hit all PX4 + minimOSD users)

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