If anyone wants to help, here are some of the functions I didn't find:
#include "stubs_asm.h"
NHSTUB(AllocateUncacheableMemory, 0xFF8389D8)
NHSTUB(GetDrive_ClusterSize, 0xDEADC0DE)
NHSTUB(GetDrive_TotalClusters, 0xDEADC0DE)
NHSTUB(GetDrive_FreeClusters, 0xDEADC0DE)
NHSTUB(SetPropertyCase, 0xFF888A44)
NHSTUB(kbd_read_keys, 0xFF8335A8)
NHSTUB(platformsub_kbd_fetch_data, 0xFF85AE80)
NHSTUB(kbd_read_keys_r2, 0xFF85A83C)
NHSTUB(qsort, 0xDEADC0DE)
NHSTUB(TurnOffBackLight, 0xDEADC0DE)
NHSTUB(vsprintf, 0xFF820350)
NHSTUB(VbattGet, 0xDEADC0DE)
NHSTUB(GetZoomLensCurrentPoint, 0xDEADC0DE)
NHSTUB(GetZoomLensCurrentPosition, 0xDEADC0DE)
NHSTUB(RefreshPhysicalScreen, 0xFF9F8694)
NHSTUB(EnterToCompensationEVF, 0xDEADC0DE)
NHSTUB(ExitFromCompensationEVF, 0xDEADC0DE)
NHSTUB(PT_PlaySound, 0xDEADC0DE)
NHSTUB(DoAFLock, 0xDEADC0DE)
NHSTUB(UnlockAF, 0xDEADC0DE)
NHSTUB(LEDDrive, 0xDEADC0DE)
NHSTUB(WriteSDCard, 0xDEADC0DE)
NHSTUB(PostLogicalEventForNotPowerType, 0xDEADC0DE)
NHSTUB(apex2us, 0xDEADC0DE)
// null sub - point these at nullsub_1 as labelled in IDA
NHSTUB(kbd_pwr_off, 0xDEADC0DE)
NHSTUB(kbd_pwr_on, 0xDEADC0DE)
NHSTUB(Mount_FileSystem, 0xDEADC0DE)
NHSTUB(Unmount_FileSystem, 0xDEADC0DE)
NHSTUB(SetZoomActuatorSpeedPercent, 0xDEADC0DE)
NHSTUB(rewinddir, 0xDEADC0DE)
NHSTUB(UpdateMBROnFlash, 0xDEADC0DE)
NHSTUB(GetOpticalTemperature, 0xDEADC0DE)
NHSTUB(Open, 0xFF8353B0)
NHSTUB(Close, 0xFF835408)
NHSTUB(Write, 0xFF835498)
NHSTUB(lseek, 0xFF835524)
NHSTUB(mkdir, 0xFF83587C)
NHSTUB(Remove, 0xDEADC0DE)
NHSTUB(malloc, 0xFF8140DC)
NHSTUB(free, 0xFF814138)
NHSTUB(strcmp, 0xFF8203A8)
NHSTUB(rename, 0xDEADC0DE)
NHSTUB(opendir, 0xFFA7E0B0)
NHSTUB(ReadFastDir, 0xDEADC0DE)
NHSTUB(stat, 0xDEADC0DE)
NHSTUB(kbd_p2_f, 0xFF832ECC)
NHSTUB(strlen, 0xFF81400C)
NHSTUB(strcpy, 0xFF82038C)
NHSTUB(SetFileTimeStamp, 0xDEADC0DE)
//implemented in the wrappers, in C
//NHSTUB(strrchr, 0xDEADC0DE)
//NHSTUB(strncpy, 0xDEADC0DE)
And here are some functions that needs to be verified (the partial matches)
// !!! THIS FILE IS GENERATED. DO NOT EDIT. !!!
#include "stubs_asm.h"
NSTUB(AllocateMemory, 0xffa9eda0)
// Best match: 56%
NSTUB(AllocateUncacheableMemory, 0xff8389e4)
// ERROR: Close is not found!
NSTUB(CreateTask, 0xff81e5b4)
NSTUB(DeleteFile_Fut, 0xff834d94)
// ERROR: EnterToCompensationEVF is not found!
NSTUB(ExecuteEventProcedure, 0xff884e58)
// ERROR: ExitFromCompensationEVF is not found!
// Best match: 57%
NSTUB(ExitTask, 0xff81e844)
NSTUB(Fclose_Fut, 0xff834f10)
NSTUB(Feof_Fut, 0xff8350fc)
NSTUB(Fflush_Fut, 0xff835138)
NSTUB(Fgets_Fut, 0xff835064)
NSTUB(Fopen_Fut, 0xff834ed0)
NSTUB(Fread_Fut, 0xff834fbc)
NSTUB(FreeMemory, 0xffa9ed98)
// Best match: 91%
NSTUB(FreeUncacheableMemory, 0xff838a18)
NSTUB(Fseek_Fut, 0xff8350b0)
NSTUB(Fwrite_Fut, 0xff835010)
// Best match: 52%
NSTUB(GetBatteryTemperature, 0xff85e2ac)
// Best match: 52%
NSTUB(GetCCDTemperature, 0xff85e238)
// Best match: 85%
NSTUB(GetCurrentAvValue, 0xff9446cc)
// Best match: 64%
NSTUB(GetCurrentTargetDistance, 0xff942ca0)
// ERROR: GetDrive_ClusterSize is not found!
// ERROR: GetDrive_FreeClusters is not found!
// ERROR: GetDrive_TotalClusters is not found!
// Best match: 75%
NSTUB(GetFocusLensSubjectDistance, 0xffa9c098)
// ERROR: GetOpticalTemperature is not found!
// Best match: 96%
NSTUB(GetParameterData, 0xff979b1c)
// Best match: 72%
NSTUB(GetPropertyCase, 0xff888b48)
// Best match: 96%
NSTUB(GetSystemTime, 0xffa9edf8)
// Best match: 74%
NSTUB(GetZoomLensCurrentPoint, 0xff947174)
NSTUB(GetZoomLensCurrentPosition, 0xffa904e8)
// Best match: 77%
NSTUB(IsStrobeChargeCompleted, 0xff8c3a24)
NSTUB(LocalTime, 0xff882754)
// Best match: 93%
NSTUB(LockMainPower, 0xff8909b0)
// ERROR: Lseek is not found!
// Best match: 92%
NSTUB(MakeDirectory_Fut, 0xff834e08)
// Best match: 57%
NSTUB(MoveFocusLensToDistance, 0xffb08258)
// Best match: 58%
NSTUB(MoveZoomLensWithPoint, 0xffa9c980)
// Best match: 62%
NSTUB(NewTaskShell, 0xff8885f4)
// ERROR: Open is not found!
NSTUB(Read, 0xff81ab78)
// ERROR: ReadFastDir is not found!
// ERROR: RefreshPhysicalScreen is not found!
// ERROR: Remove is not found!
// Best match: 53%
NSTUB(RenameFile_Fut, 0xff834ecc)
// ALT: NSTUB(RenameFile_Fut, 0xffa65670) // 8/7
// ALT: NSTUB(RenameFile_Fut, 0xffa656c0) // 8/7
// Best match: 93%
NSTUB(SetAutoShutdownTime, 0xff890a24)
// Best match: 55%
NSTUB(SetFileTimeStamp, 0xff932af4)
// Best match: 96%
NSTUB(SetParameterData, 0xff979a8c)
// Best match: 84%
NSTUB(SetPropertyCase, 0xff874698)
// Best match: 92%
NSTUB(SleepTask, 0xff83865c)
// Best match: 60%
NSTUB(TakeSemaphore, 0xff838324)
// ERROR: TurnOffBackLight is not found!
// Best match: 54%
NSTUB(TurnOnBackLight, 0xff89e2a0)
// ERROR: UIFS_WriteFirmInfoToFile is not found!
// Best match: 93%
NSTUB(UnlockMainPower, 0xff890904)
// ERROR: UpdateMBROnFlash is not found!
// ERROR: VbattGet is not found!
// ERROR: Write is not found!
NSTUB(_log, 0xffb3bc5c)
NSTUB(_log10, 0xffb3a8e8)
NSTUB(_pow, 0xffb3aa58)
NSTUB(_sqrt, 0xffb3d8e0)
NSTUB(close, 0xff81a990)
// Best match: 71%
NSTUB(closedir, 0xffa7e380)
// Best match: 71%
NSTUB(closefastdir, 0xffa7e380)
// ERROR: free is not found!
// Best match: 86%
NSTUB(kbd_p1_f, 0xff833624)
// Best match: 86%
NSTUB(kbd_p1_f_cont, 0xff833630)
// ERROR: kbd_p2_f is not found!
// Best match: 51%
NSTUB(kbd_pwr_off, 0xff85ae98)
// ERROR: kbd_pwr_on is not found!
// ERROR: kbd_read_keys is not found!
// Best match: 69%
NSTUB(kbd_read_keys_r2, 0xff85a858)
// ERROR: lseek is not found!
// ERROR: malloc is not found!
NSTUB(memcmp, 0xff8203e8)
NSTUB(memcpy, 0xff83df94)
NSTUB(memset, 0xff9fbfa0)
// ERROR: mkdir is not found!
NSTUB(mktime_ext, 0xff8a5d68)
NSTUB(open, 0xff81a8e0)
// ERROR: opendir is not found!
// ERROR: openfastdir is not found!
// ERROR: qsort is not found!
// Best match: 95%
NSTUB(rand, 0xff8204f0)
NSTUB(read, 0xff81ab78)
// ERROR: readfastdir is not found!
// ERROR: rename is not found!
// Best match: 95%
NSTUB(srand, 0xff8204e4)
// ERROR: stat is not found!
// Best match: 61%
NSTUB(strcat, 0xff813f38)
// Best match: 56%
NSTUB(strchr, 0xff813fc0)
// ERROR: strcmp is not found!
// Best match: 77%
NSTUB(strcpy, 0xff813f20)
NSTUB(strftime, 0xff8a5770)
// Best match: 79%
NSTUB(strlen, 0xff8203c4)
NSTUB(strncmp, 0xff813f74)
// Best match: 73%
NSTUB(strncpy, 0xff813f38)
// Best match: 71%
NSTUB(strrchr, 0xff83df6c)
// ALT: NSTUB(strrchr, 0xff8a5538) // 18/8
// Best match: 96%
NSTUB(strtol, 0xff83e274)
// Best match: 86%
NSTUB(time, 0xff882ccc)
// ERROR: vsprintf is not found!
NSTUB(write, 0xff81abd8)