Back with the debug patchs:
Unfortunately the camera logs show it's not quite the same as sx170, as the dvlp task does not get hit with the correct args.
Excerpt from IXUS160 logs:
00271510: UI:_ContiCount->0(5632)
00271510: UI:_ManagePTMProperty
00271510: SS:ModChg
00271510: SS: Evf=1
00271510: SS: 8241->8000
00271510: SS: Asp 0000->0000
00271520: SS:ModChg*
00271520: UI:_DecideCaptureMode
00271520: UI:_StillToStill
00271520: UI:_StartStill
00271520: UI:_ContiCount->0(5632)
00271520: UI:DSIC:42,2
00271530: UI:DSIC:d3,0
00271560: UI:Display_CaptInfo
00271570: UI:VTMUnLock
00271570: UI:TerminateDeliverToZoomController
00271570: UI:OPTICAL_ZOOM_POS
00271570: UI:UnpressZoomLever
00271570: UI:DispSwCon_TurnOnDisplayDevice
00271570: UI:LogicalEvent:0x0000313e:adr:0,Para:0
00271590: UI:DSIC:d5,0
00271590: UI:VTMLock
00271600: UI:VTMUnLock
00271600: UI:_DecideModeDial
00271610: UI:LogiEvnt_NotPowerType:0x000009a4:adr:0,Para:0
00271610: UI:LogiEvnt_NotPowerType:0x000009a2:adr:0,Para:0
00271610: UI:DSIC:6a,0
00272400: UI:Button:0x000009A1:PressSwOne
00272400: SS:PreBuf
00272400: SS:BitR
00272400: UI:ShtCon_ResetShootingNumber
00272400: UI:ShootState:0x1
00272400: UI:ShtCon_Activate
00272400: UI:DispSw: Lock
00272400: UI:ShtCon_ShutDownRecModeMenu
00272400: UI:DSIC:61,0
00272400: UI:VTMLock
00272400: UI:VTMUnLock
00272410: UI:VTMLock
00272410: UI:VTMReduuce
00272410: UI:LogicalEvent:0x00003136:adr:0,Para:0
00272410: UI:ShtCon_PrepareCapture
00272410: SS:PreCapt
00272410: UI:ShootState:0x2
00272410: UI:ClearEventComp
00272420: UI:VTM SW
00272420: UI:VTMUnLock
00272720: UI:ShootSeqToUI:0x0000203b:adr:0,Para:0
00272730: UI:ShtCon_SetAFBeep
00272730: UI:DSIC:69,0
00272870: UI:ShootSeqToUI:0x00002006:adr:0x1d5c,Para:7516
00272870: 000c83a3:capt 0
00272870: UI:ShtCon_SetPreCapt
00272870: UI:DSIC:62,1
00272870: UI:VTMLock
00272870: UI:DSIC:d5,0
00272890: UI:Button:0x000009A3:PressSwTwo
00272900: UI:VTMUnLock
00272900: UI:_ResetShootingMode
00272900: UI:_EntryPrepareShoot
00272900: UI:ShootState:0x6
00272910: UI:ShootState:0x7
00272910: UI:ShootState:0x18
00272910: UI:DSIC:12,0
00272910: UI:_MuteOn
00272910: UI:DSIC:43,0
00272910: UI:DispSwCon_MuteOnPhysicalScreen
00272910: UI:Window MuteOn
00272910: UI:MuteOnPhysicalScreen
00272910: SS:StartShoot
00272910: SS:SCtrl:Shoot(1/0x1)
00272920: UI:Button:0x000009A4:UnpressSwTwo
00272920: UI:Button:0x000009A2:UnpressSwOne
00272930: 000d6589:capt 4
00272930: UI:ShootSeqToUI:0x0000203f:adr:0xff99a090,Para:-6709104
00272930: UI:_CaptureCount->1
00272930: UI:DSIC:63,0
00272930: UI:VTMLock
00272940: UI:VTMUnLock
00272940: UI:VTMLock
00272950: UI:VTMReduuce
00272950: UI:VTMLock
00272950: UI:VTMReduuce
00272950: UI:DSIC:6a,0
00272950: UI:VTM SW
00272950: UI:VTMUnLock
00272950: UI:_MuteOff
00272950: UI:DSIC:44,0
00272950: UI:DispSwCon_MuteOffPhysicalScreen
00272950: UI:Window MuteOff
00272950: UI:MuteOffPhysicalScreen
00272980: UI:ShootSeqToUI:0x00002040:adr:0x581a38,Para:5773880
00272980: UI:DSIC:64,0
00273810: 000ad421:capt 2
00273810: 000aeb60:dvlp q1 0 1 1cab0, 0
00273810: UI:DSIC:45,0
00274300: SS:SCtrl:RecReview
00274300: SS:SCtrl:StartReview
00274300: UI:ShootSeqToUI:0x00002041:adr:0x1c974,Para:117108
00274460: UI:ShootSeqToUI:0x0000203e:adr:0,Para:0
00274460: UI:ShootSeqToUI:0x00002001:adr:0x582e68,Para:5779048
00274460: UI:Sht_CancelStrobeChargeTimer
00274460: UI:DSIC:4c,0
00274460: UI:VTMLock
00274460: UI:VTMUnLock
00274460: SS:SCtrl:NextShot(1)
00274460: UI:DSIC:46,0
00274460: UI:_CaptureStanbyForReview
00274460: SS:SCtrl:CompShootPic(0)
00274460: UI:ShootSeqToUI:0x00002029:adr:0x1c980,Para:117120
00274460: UI:_NormalCompleteShootPictureAction
00274460: UI:_CheckNextShotAvailable
00274470: UI:_CaptureCount->0
00274470: UI:ShtCon_ResetShootingNumber
00274470: UI:ShootState:0x8
00274470: UI:ShtCon_StartReview
00274470: UI:_EntryActionReview
00274470: UI:LogicalEvent:0x0000311f:adr:0,Para:0
00274470: UI:_EnableReviewHold:IsPressSwTwo:0
00274470: UI:_EnableReviewHold:IsAvailableShots:1
00274470: UI:RecReviewCon_SetMode:0x0003
00274470: UI:DSIC:4c,0
00274470: UI:VTMLock
00274470: UI:VTMReduuce
00274470: SS:StopRev
00274470: UI:VTMLock
00274470: UI:PB.StartDecodeRecReview_S
00274480: UI:PB.RefPB
00274490: UI:IPS.DrawI
00274490: SS:NextAvail(11),ReviewAvail(9)
00274510: UI:PB.StartDecodeRecReview_E
00274510: UI:StartRecReviewTimer
00274510: UI:ShootState:0x9
00274510: UI:ShtCon_ResetShootingNumber
00274510: SS:ExitShoot
00274710: UI:IPS.DComp:0
00274710: UI:LogicalEvent:0x00003204:adr:0,Para:0
00277330: UI:DSIC:47,0
00278450: UI:DSIC:48,0
00278470: 0001ee65:capt 3
00278470: UI:LogicalEvent:0x0000311e:adr:0,Para:0
00278470: UI:PB.RfrsI
00278480: UI:DispSwCon_MuteOffPhysicalScreen
00278480: UI:Window Reduce MuteOff
00278480: UI:VTMUnLock
00278480: UI:Window Re MuteOff
00278480: UI:Window MuteOff
00278480: UI:MuteOffPhysicalScreen
00278480: UI:_EntryPrepareRecreviewOff
00278480: UI:ShootState:0xB
00278480: UI:ShtCon_StopReview
00278480: UI:StopRecReviewController
00278480: UI:PB.StopDecodeRecReview_S
00278480: UI:PB.StopR
00278480: UI:VTMLock
00278490: UI:VTMReduuce
00278490: UI:LogicalEvent:0x00003120:adr:0,Para:0
00278490: UI:PB.StopDecodeRecReview_E
00278490: UI:ShtCon_ResetShootingNumber
00278490: UI:_ExitSequence
00278490: UI:Sht_CancelStrobeChargeTimer
00278490: UI:DSIC:4c,0
00278490: UI:VTMLock
00278490: UI:VTMReduuce
00278490: UI:_ExitActionReview
00278490: SS:CancelPre
00278720: UI:VTMLock
00278720: UI:VTMUnLock
00278860: UI:DispSwCon_MuteOffPhysicalScreen
00278860: UI:Window MuteOff
00278860: UI:MuteOffPhysicalScreen
00278860: UI:ShootState:0x0
00278860: UI:ShtCon_Deactivate
00278860: UI:DSIC:12,0
00278870: UI:DSIC:60,0
00278870: UI:DispSwCon_TurnOnDisplayDevice
00278870: UI:VTMLock
00278870: UI:DSIC:d5,0
00278900: UI:VTMUnLock
00278900: UI:DispSw: Unlock
00278900: UI:DispSwCon:Unlock
00278900: UI:_ChangeDisplayOut
00278900: UI:TerminateDeliverToZoomController
00278900: UI:OPTICAL_ZOOM_POS
00278900: UI:UnpressZoomLever
00278900: UI:VTMLock
00278900: UI:VTMReduuce
00278900: UI:VTMLock
00278900: UI:VTMReduuce
00278900: UI:_EntryIdleShoot
00278910: UI:ShootState:0x0
00278910: UI:VTM SW
00278910: UI:VTMReduuce
00278910: UI:VTM SW
00278910: UI:VTMReduuce
00278910: UI:VTM SW
00278910: UI:VTMUnLock
00278960: UI:VTMLock
00278960: UI:VTMUnLock
00278960: SS:ChargeComplete
00281630: UI:VTMLock
00281630: UI:VTMUnLock
00282330: UI:VTMLock
00282340: System.Create
00282340: StartRedirectUART
00282340: UI:VTMUnLock
00282350: Printf
00282350: ShowCameraLog
uartr.lua: start UART redirection
(capt indexes are a little bit different, in ixus160 what is called capt 4 is capt 3 in sx170 and capt3 was not in sx170, sorry about that)
So looking at dvlp lines, there is no "dvlp q1 3 x x, x" so the "" BEQ loc_FF99BD38 \n" // 1st msg after shoot" never gets hit.
Successfully tested with putting the debug func at "loc_FF99BD44:\n", I can increment the value.
There is also no SS Raw event, but I don't know if it's just the camera.
(didn't implement the fwt log hooks)
We can also see that the capt 2 call is actually earlier than the dvlp call, so no point if I understood right to put it in dvlpseqtask.