Liaison rc not found

bonjour,
j’ai un probleme
depuis 2 ,ans ,je mets regulierement a jour les firmware arducopter.
a partir de 4.5.6 et apres ,la liaison rc est perdue…je reviens à la version 4.5.5 et tout est OK

je ne trouve pas de reponse !!!
je peux rester avec cette version sans probleme mais j’aime pas rester sur un echec
merci beaucoup

firmware 4.5.5
elrs 3.5.1
FC diatone mamba F405 mk4 mini
[arducopter 4.5.5
3 01-01-1970 01-00-00.bin (165.5 KB)
num POST TUNE.param|attachment](upload://hr6WUveCpD6VoDAWgnGbUF0srqr.param) (19.6 KB)

Hello I have a problem For the past 2 years, I have been regularly updating the Arcopopter firmware. From 4.5.6 and after, the RC link is lost… I’m going back to version 4.5.5 and everything is OK I can’t find an answer!! I can stay with this version without problem but I don’t like to stay on a failure Thank you very much

From the hardware information:

SERIAL1  PPM / SBUS   RC Input (SBUS pin MUST be used for RC input unless alt config used)
 	PPM->RX1     SBUS->TX1

Do you have the RC signal wire connected to Serial1 RX1 or TX1? In some diagrams it is labeled as PPM and SBUS.
You might just have to BRD_ALT_CONFIG,1 back to 0

MERCI POUR LA REPONSE EXPRESS,

le Tx emetteur est sur Rx de la fc (et inversement)
et BRD_ALT_CONFIG =0 ne change rien,
j’ai toujours RC not found

merci