I have the same issue. RPi3, freshly installed Recalbox 8.
Recalbox boots up and I successfully get a video signal via composite.
But it stops at the "ghosts" splash screen, because Emulationstation fails to start up, with es_log.txt showing:
[2021/12/05 02:50:10.015] (INFO ) : [StaticLifeCycleControler] RecalboxConf instance created.
[2021/12/05 02:50:10.015] (INFO ) : [StaticLifeCycleControler] NotificationManager instance created.
[2021/12/05 02:50:10.016] (INFO ) : [MainRunner] EmulationStation - v 8.0-Electron, built Dec 1 2021 - 13:30:17
[2021/12/05 02:50:10.016] (WARN!) : [Locale] /usr/bin/locale/lang/en_US/LC_MESSAGES/emulationstation2.mo not found.
[2021/12/05 02:50:10.017] (WARN!) : [Locale] /usr/bin/locale/lang/en/LC_MESSAGES/emulationstation2.mo not found.
[2021/12/05 02:50:10.017] (WARN!) : [Locale] /usr/share/locale/en_US/LC_MESSAGES/emulationstation2.mo not found.
[2021/12/05 02:50:10.017] (INFO ) : [Locale] Using /usr/share/locale/en/LC_MESSAGES/emulationstation2.mo
[2021/12/05 02:50:10.114] (ERROR) : [SDL2] Fatal error initializing SDL 2
Which seems to be tried repeatedly, since recalbox.log fills up with:
[ 32.93] [emulationstation-starter] [ES] started emulationstation (pid=1707)
[ 33.12] [emulationstation-starter] [ES] emulationstation exited code 134
[ 33.13] [emulationstation-starter] [ES] started emulationstation (pid=1715)
[ 33.32] [emulationstation-starter] [ES] emulationstation exited code 134
[ 33.33] [emulationstation-starter] [ES] started emulationstation (pid=1723)
[ 33.54] [emulationstation-starter] [ES] emulationstation exited code 134
[ 33.54] [emulationstation-starter] [ES] started emulationstation (pid=1731)
[ 33.74] [emulationstation-starter] [ES] emulationstation exited code 134
[ 33.74] [emulationstation-starter] [ES] started emulationstation (pid=1739)
[ 33.94] [emulationstation-starter] [ES] emulationstation exited code 134
[ 33.94] [emulationstation-starter] [ES] started emulationstation (pid=1747)
EDIT: Configured according to the wiki, i.e.
in recalbox-user-config.txt
sdtv_mode=2
hdmi_ignore_hotplug=1
audio_pwm_mode=2
and in recalbox.conf
global.videomode=default
