3DS firmware integrity checker

ctrcheck.gm9

# A script for checking all of a 3DS console's important files and their integrity.
# original script by FrozenFire
# overhaul, fixes, and current maintenance by StarlitSkies
# last modified: 2024-09-23
# version: 3.1.0
# if you didn't get this file from https://gist.github.com/StarlitSkies/f417c1ded9de8fceffdb532f92823377/, go there and make sure this copy wasn't tampered with

# latest changelog:
# refactor a bunch of things
# reduce reliance on nested ifs so i can use more labels without the script exploding
# fix a couple checks that were written backwards
# add checks for blank data in SecureInfo and LFCS to match the other essentials
# detect CHN/KOR/TWN regions in SecureInfo checks
# standardize format of some warnings, such as 'data is invalid' and 'is an invalid size'
# and all checks now include misc files

@cleanup
set FULL "0"

set NANDSECTORS_LOG ""
set ESSENTIALS_LOG ""
set CTRNAND_LOG ""
set TWLNAND_LOG ""
set FIRM_LOG ""
set SD_LOG ""
set RAM_LOG ""
set LOG "disabled"

@menu
labelsel -o -s "Select which parts of the system to check.\nConsole is a $[REGION] $[RDTYPE] $[ONTYPE] using $[HAX].\nCurrent id0 is $[SYSID0].\n\nPermanent logging: $[LOG]" check_*
goto menu

@check_All
set FULL "1"
goto NAND_Header

@check_NAND_Only
goto NAND_Header

@check_SD_Only
goto SD_Files

@NAND_Header
# check whether NAND header signature is sighax, based on hashes
# sighax will always be read as valid by boot9 even without cfw, so it's just used to check whether custom partitions should be possible
set SIGHAX "0"
if find S:/nand_hdr.bin NULL
    if not shaget S:/nand_hdr.bin@0:200 NULL
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Error: NAND header is an invalid size.\n"
        goto NAND_Sectors
    end
else
    set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Error: NAND header not found.\n"
    goto NAND_Sectors
end

if sha S:/nand_hdr.bin@0:100 A4AE99B93412E4643E4686987B6CFD59701D5C655CA2FF671CE680B4DDCF0948
    set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Information: NAND header's signature is sighax.\n"
    set SIGHAX "1"
end

# hash-based check of NAND header partition table against retail partition tables
if sha S:/nand_hdr.bin@100:60 dfd434b883874d8b585a102f3cf3ae4cef06767801db515fdf694a7e7cd98bc2
    if chk $[ONTYPE] "N3DS"
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Information: NAND header is stock. (n3DS)\n"
    else
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Critical: o3DS has an n3DS NAND header.\n"
    end
elif sha S:/nand_hdr.bin@100:60 ae9b6645105f3aec22c2e3ee247715ab302874fca283343c731ca43ea1baa25d
    if chk $[ONTYPE] "O3DS"
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Information: NAND header is stock. (o3DS)\n"
    else
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Critical: n3DS has an o3DS NAND header.\n"
    end
else
    fget S:/nand_hdr.bin@100:4 NCSD
    #check for the NCSD magic header, if it's not present then there's definitely something wrong
    if chk $[NCSD] "4E435344"
        if chk $[SIGHAX] "1"
            set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Warning: NAND partition table is modified, but there is sighax in the NAND header.\n"
        else
            set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Error: NAND partition table is modified, and there is no sighax in the NAND header.\n"
        end
    else
        # your NAND has a minor case of serious brain damage
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Error: NAND header data is invalid. You've met with a terrible fate, haven't you?\n"
    end
end

@NAND_Sectors
# verify Secret Sector, which is doubly important for N3DSes
if chk $[ONTYPE] "N3DS" 
    if not sha S:/sector0x96.bin 82F2730D2C2DA3F30165F987FDCCAC5CBAB24B4E5F65C981CD7BE6F438E6D9D3
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Warning: Secret Sector data is invalid. a9lh might be installed.\n"
    end
else
    if fget S:/nand.bin@12C00:2 SBYTE
        if chk -u $[SBYTE] "0000"
            if chk -u $[SBYTE] "FFFF"
                set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Warning: There may be a9lh leftovers in the secret sector.\n"
            end
        end
    else
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Critical: NAND is unreadable at offset 0x12C00...?\n"
    end
end

# verify the TWL MBR exists and is retail (there is no good reason this should ever be modified)
if find S:/twlmbr.bin NULL
    if not sha S:/twlmbr.bin 77a98e31f1ff7ec4ef2bfacca5a114a49a70dcf8f1dcd23e7a486973cfd06617
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Critical: TWL MBR data is invalid.\n"
    end
else
    set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Critical: TWL MBR not found.\n"
end

# get first byte in stage2 location
if not fget S:/nand.bin@B800000:1 ABYTE
    set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Critical: NAND is unreadable at offset 0xB800000...?\n"
end
# instead of checking the full sector against multiple stage2s, this just checks if the sector is "clean"
# (if first byte is not "clean" assume stage2 is there, can be done in a better way)
# if stage2 was replaced with trash it would trigger this warning tho
if chk -u $[ABYTE] "00"
    if chk -u $[ABYTE] "FF"
        set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Warning: There are likely leftovers from a9lh's stage2 payload.\n"
    end
end

# check for presence of bonus drive, just because it might come in handy to know sometimes
if isdir 8:
    set NANDSECTORS_LOG "$[NANDSECTORS_LOG]Information: Bonus drive is enabled.\n"
end


@CTRNAND
# check if CTRNAND can be accessed, skip all CTRNAND checks if it isn't
if not isdir 1:
    set CTRNAND_LOG "$[CTRNAND_LOG]Error: CTRNAND not found.\n"
    goto TWLNAND
end

# find movable.sed, check if it's valid, and check whether CMAC is set correctly based on size (288 bytes vs 320 bytes)
set MLFCSHASH ""
if not find 1:/private/movable.sed movable
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: movable.sed not found.\n"
    goto LFCS
end
if shaget $[movable]@0:100 NULL
    fget $[movable]@8:10 ISVALID
    if chk $[ISVALID] "00000000000000000000000000000000"
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Warning: movable.sed's copy of LFCS is blank.\n"
    end
else
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: movable.sed is an invalid size.\n"    
    goto LFCS
end
fget $[movable]@0:4 SEED
fget $[movable]@5:1 CMAC
shaget $[movable]@8:110 MLFCSHASH
#check if movable.sed at least has the SEED magic header, then check whether CMAC is set correctly based on size (320 vs 288 bytes)
if chk -u $[SEED] "53454544"
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: movable.sed data is invalid.\n"
elif chk $[CMAC] "01"
    if not fget $[movable]@120:1 NULL
        if ask "movable.sed is misconfigured.\nPress (A) to reconfigure it to normal values."
            fset $[movable]@5 00
            set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Information: movable.sed has been fixed by removing the CMAC flag.\n"
        else
            set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: movable.sed is 288 bytes but has the CMAC flag.\n"
        end
    end
end

@LFCS
# find LFCS, check if it's valid, check if it's the same as movable.sed's copy of LFCS, and check against OTP seed that's used to make part of LFCS
# account for both potential filenames of LocalFriendCodeSeed
if find 1:/rw/sys/LocalFriendCodeSeed_B LFCS
elif find 1:/rw/sys/LocalFriendCodeSeed_A LFCS
else
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: LFCS not found.\n"
    goto SecureInfo
end
if shaget $[LFCS]@0:100 NULL
    fget $[LFCS]@0:10 ISVALID
    if chk $[ISVALID] "00000000000000000000000000000000"
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: LFCS data is invalid.\n"
        goto SecureInfo
    end
else
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: LFCS is an invalid size.\n"
    goto SecureInfo
end 
shaget $[LFCS]@0:110 LFCSHASH
# compare the LFCS in movable.sed to the raw LFCS file, if movable.sed exists
if chk -u $[MLFCSHASH] ""
    if chk -u $[MLFCSHASH] $[LFCSHASH]
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Information: LFCS doesn't match movable.sed.\n"
    end
end
if find M:/otp_dec.mem OTP    
    fget $[LFCS]@108:8 LFCSEED
    fget $[OTP]@8:8 OTPSEED
    if chk -u $[LFCSEED] $[OTPSEED]
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Warning: Console is using a donor LFCS.\n"
    end
end

@SecureInfo
# find secureinfo_(a/b) and check if it's valid 
set SECVALID "0"
if find 1:/rw/sys/SecureInfo_A SEC
elif find 1:/rw/sys/SecureInfo_B SEC
else
    if find 1:/rw/sys/SecureInfo_C ALTSEC
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Warning: SecureInfo not found, but SecureInfo_C exists.\n"
    else
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: SecureInfo not found.\n"
    end
    goto HWCAL0
end
if not find -s 1:/rw/sys/SecureInfo_C ALTSEC
    set ALTSEC ""
end
if not shaget $[SEC]@0:110 NULL
    if shaget $[ALTSEC]@0:110 NULL
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Warning: SecureInfo is an invalid size, but SecureInfo_C exists and is valid.\n"
    else
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: SecureInfo is an invalid size.\n"
    end
    goto HWCAL0
end
# the checks here are done against the end of the file since that part contains the serial; the RSA signature isn't important for troubleshooting purposes
fget $[SEC]@100:10 ISVALID
if chk $[ISVALID] "00000000000000000000000000000000"
    if chk $[ALTSEC] ""
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: SecureInfo data is invalid, and there is no SecureInfo_C.\n"
    else
        fget $[ALTSEC]@100:10 ISVALID
        if chk $[ISVALID] "00000000000000000000000000000000"
            set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: SecureInfo and SecureInfo_C data are both invalid.\n"
        else
            set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Warning: SecureInfo data is invalid, but SecureInfo_C exists and is valid.\n"
        end
    end
    goto HWCAL0
else
    set SECVALID "1"
    fget $[SEC]@10C:1 SECSERIALCHECK
    if chk $[SECSERIALCHECK] "00"
        fget $[SEC]@102:0A SECSERIAL
    else
        fget $[SEC]@102:0B SECSERIAL
    end
end

# then check if it matches the console region, check for region change (presence of secureinfo_c), and use that for both data comparison and to see what region was changed to
if chk -u $[ALTSEC] ""
    set REGCHG "1"
    fget $[ALTSEC]@100:1 ALTREGSEC
    if chk $[ALTREGSEC] "00"
        set ALTREG "JPN"
    elif chk $[ALTREGSEC] "01"
        set ALTREG "USA"
    elif chk $[ALTREGSEC] "02"
        set ALTREG "EUR"
    elif chk $[ALTREGSEC] "04"
        set ALTREG "CHN"
    elif chk $[ALTREGSEC] "05"
        set ALTREG "KOR"
    elif chk $[ALTREGSEC] "06"
        set ALTREG "TWN"
    end
else 
    set REGCHG "0"
end
fget $[SEC]@100:1 REGSEC
if chk $[REGSEC] "00"
    set REG "JPN"
elif chk $[REGSEC] "01"
    set REG "USA"
elif chk $[REGSEC] "02"
    set REG "EUR"
elif chk $[REGSEC] "04"
    set REG "CHN"
elif chk $[REGSEC] "05"
    set REG "KOR"
elif chk $[REGSEC] "06"
    set REG "TWN"
end
if chk -u $[REG] $[REGION]
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Warning: SecureInfo doesn't match the console's region.\n"
end
if chk $[REGCHG] "1"
    if chk -u $[ALTREG] $[REGION]
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Information: Console's region is changed from $[REG] to $[ALTREG].\n"
    else
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Information: SecureInfo_C exists, but console's region is unchanged.\n"
    end
end

@HWCAL0
# check whether first HWCAL exists
if find 1:/ro/sys/HWCAL0.dat HWCAL0
    if not shaget $[HWCAL0]@0:900 NULL
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: HWCAL0 is an invalid size.\n"
        goto HWCAL1
    end
else
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: HWCAL0 not found.\n"
    goto HWCAL1
end
# if it's valid, check if it has the CCAL magic header
fget $[HWCAL0]@0:4 CCAL
if chk -u $[CCAL] "4343414C"
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: HWCAL0 data is invalid.\n"
end

@HWCAL1
# check whether second HWCAL exists
if find 1:/ro/sys/HWCAL1.dat HWCAL1
    if not shaget $[HWCAL1]@0:900 NULL
        set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: HWCAL1 is an invalid size.\n"
        goto Misc_CTRNAND
    end
else
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: HWCAL1 not found.\n"
    goto Misc_CTRNAND
end
# if it's valid, check if it has the CCAL magic header
fget $[HWCAL1]@0:4 CCAL
if chk -u $[CCAL] "4343414C"
    set ESSENTIALS_LOG "$[ESSENTIALS_LOG]Critical: HWCAL1 data is invalid.\n"
end

@Misc_CTRNAND
# check whether system can boot without SD card
if find 1:/boot.firm NULL
    if find 1:/rw/luma/payloads/GodMode9.firm NULL
        set CTRNAND_LOG "$[CTRNAND_LOG]Information: GodMode9 and Luma3DS are in the NAND.\n"
    else
        set CTRNAND_LOG "$[CTRNAND_LOG]Information: Luma3DS is in the NAND, but GodMode9 isn't.\n"
    end
else
    set CTRNAND_LOG "$[CTRNAND_LOG]Warning: Luma3DS is not in the NAND.\n"
end

# check whether nand title database exists
if find 1:/dbs/title.db NANDTITLEDB
    if shaget $[NANDTITLEDB]@0:400 NULL
        fget $[NANDTITLEDB]@100:4 DIFF
        # check whether nand title.db has the DIFF magic header
        if chk -u $[DIFF] "44494646"
            set CTRNAND_LOG "$[CTRNAND_LOG]Critical: CTRNAND title.db data is invalid.\n"
        end
    else
        set CTRNAND_LOG "$[CTRNAND_LOG]Critical: CTRNAND title.db is an invalid size.\n"
    end
else
    set CTRNAND_LOG "$[CTRNAND_LOG]Critical: CTRNAND title.db not found.\n"
end

@TWLNAND
#check if TWLNAND can be accessed
if not isdir 2:
    set TWLNAND_LOG "$[TWLNAND_LOG]Error: TWLNAND not found.\n"
    goto TWLP
end
# the console won't boot if shared2 doesn't exist, but remaking it is easy and harmless
if not isdir 2:/shared2
    if ask "A folder required to boot is missing. Press (A) to fix this issue."
        mkdir 2:/shared2
        set TWLNAND_LOG "$[TWLNAND_LOG]Information: shared2 has been recreated.\n"
    else 
        set TWLNAND_LOG "$[TWLNAND_LOG]Critical: shared2 not found.\n"
    end
end
# check for inspect.log, and if it exists, compare its copy of the serial number against SecureInfo
if isdir 2:/sys/log
    if find 2:/sys/log/inspect.log INSPECTLOG
        if chk $[SECVALID] "1"
            fget $[INSPECTLOG]@77:1 TWLNSERIALCHECK
            if chk $[TWLNSERIALCHECK] "0a"
                fget $[INSPECTLOG]@6D:0A TWLNSERIAL
            else
                fget $[INSPECTLOG]@6D:0B TWLNSERIAL
            end
            if chk -u $[SECSERIAL] $[TWLNSERIAL]
                set TWLNAND_LOG "$[TWLNAND_LOG]Warning: inspect.log serial does not match SecureInfo.\n"
            end
        end
    else
        set TWLNAND_LOG "$[TWLNAND_LOG]Warning: inspect.log not found.\n"
    end
else
    set TWLNAND_LOG "$[TWLNAND_LOG]Warning: 2:/sys/log folder not found, meaning inspect.log also not found.\n"
end

@TWLP
# you don't need TWLP to boot (or for a lot of things, really), but it's still good to check everything's in place
if not isdir 3:
    set TWLNAND_LOG "$[TWLNAND_LOG]Warning: TWLP not found.\n"
end

@FIRM_Data
# basic checks for how many FIRM partitions exist and which ones they are
set FIRMEXIST "0"
set ALTFIRMEXIST "0"
set BONUSFIRMS "0"
set TOOMANYFIRMS "0"
if find S:/firm0.bin NULL
    set FIRMEXIST "1"
end
if find S:/firm1.bin NULL
    set ALTFIRMEXIST "1"
end
if find S:/firm2.bin NULL
    set BONUSFIRMS "1"
end
if find S:/firm5.bin NULL
    set TOOMANYFIRMS "1"
end
if chk $[FIRMEXIST] "0"
    if chk $[ALTFIRMEXIST] "0"
        set FIRM_LOG "$[FIRM_LOG]Error: FIRM0 and FIRM1 both not found. Unless you have access to ntrboot, do NOT power off the console until you've fixed this.\n"
        goto NAND_End
    else
        set FIRM_LOG "$[FIRM_LOG]Bruh Moment: FIRM0 not found, but FIRM1 exists. This shouldn't be possible, the console's probably having a stroke.\n"
    end
else
    if chk $[ALTFIRMEXIST] "0"
        set FIRM_LOG "$[FIRM_LOG]Critical: FIRM1 not found, but FIRM0 exists. The console isn't dead yet, but fix this ASAP.\n"
    end
end
if chk $[BONUSFIRMS] "1"
    if chk $[TOOMANYFIRMS] "1"
        set FIRM_LOG "$[FIRM_LOG]Bruh Moment: ...Why are there more than 4 FIRM partitions?\n"
    else
        set FIRM_LOG "$[FIRM_LOG]Information: Extra FIRM partitions detected. But hey, rules were meant to be broken, right?\n"
    end
end

# compare firm slots against the hashes of all payloads we could reasonably expect
# todo: add hashes for new b9s/fb3ds versions as they're released
for S: firm*.bin
    strsplit FIRM $[FORPATH] "/"
    strsplit -b FIRM $[FIRM] "."
    # immediately start with b9s checks since they're the most common, it speeds up the script if they get hit first
    if sha $[FORPATH]@0:3E00 72002296D1B8B1D4E462EA340124D836BA7F8D6BF16617F369ED90983C42BB98
        set FIRM_LOG "$[FIRM_LOG]Information: b9s v1.4 installed to $[FIRM].\n"
    elif sha $[FORPATH]@0:7800 79C68585B4BA1D7C4A91B858861553E768C6576B92E303810B33219736B3598B
        set FIRM_LOG "$[FIRM_LOG]Warning: b9s v1.3 installed to $[FIRM].\n"
    elif sha $[FORPATH]@0:10C00 A765E44844BD5667CC1D7A9A89AD45EC674F8392367F4418CCB08152581D7B3A
        set FIRM_LOG "$[FIRM_LOG]Warning: b9s v1.2 installed to $[FIRM].\n"
    elif sha $[FORPATH]@0:10C00 D77BEE742E7E7D528BAA20E6ADA7AC822598DDCACDFC81B1F13E32C94F4EBC50 
        set FIRM_LOG "$[FIRM_LOG]Warning: b9s v1.1 installed to $[FIRM].\n"
    elif sha $[FORPATH]@0:20800 43978C226D3164047051B1B534D6589608F1FA04E0B1766E1FDBEB3BC41707B6
        set FIRM_LOG "$[FIRM_LOG]Warning: b9s v1.0 installed to $[FIRM].\n"
    elif verify $[FORPATH]
        # check for the sighax signatures that fastboot3DS uses
        # sciresm is used when fb3DS is installed by outside sources, derrek is used if fb3DS updated itself
        # and that means you'll basically never see derrek sig in practice. be wary if you do see it
        if sha $[FORPATH]@100:100 078CC0CFD850A27093DDA2630C3603CA0C96969BD1F26DA48AC7B1BAE5DD5219
            set FIRMSIG "SciresM"
        elif sha $[FORPATH]@100:100 ADB73ABC35708EF1DFE9EF9CA5FAC8BFC2DF916BB2E38101858482409F0D450A
            set FIRMSIG "derrek"
        else 
            set FIRMSIG "none"
        end
        # minfirm is a special case, since it's only used by b9stool and shouldn't stick around for long after cfw setup. best to get it out of the way before fb3DS
        if sha $[FORPATH]@0:100 93EE0A3799072EFB368DAD3174D8DE2EC9735BC13AC78C087DA80
            set FIRM_LOG "$[FIRM_LOG]Critical: minfirm installed to $[FIRM].\n"
        elif chk -u $[FIRMSIG] "none"
            if sha $[FORPATH]@0:100 D36E802EEA55B92110438D0A3B09DFCEEEC71AEB7BF05073A2E0E857827F3903
                set FIRM_LOG "$[FIRM_LOG]Information: fb3DS v1.2 ($[FIRMSIG] sig) installed to $[FIRM].\n"
            elif sha $[FORPATH]@0:100 9C8D28272421C78AC796EB9023A6D1373F31176CB693CE1B04B1B78112E25226
                set FIRM_LOG "$[FIRM_LOG]Warning: fb3DS v1.1 ($[FIRMSIG] sig) installed to $[FIRM].\n"
            elif sha $[FORPATH]@0:100 5E58A159C057D0762E6BFC53FE5A5CDAECA338544B252B85524DFBBB1D546DCB
                set FIRM_LOG "$[FIRM_LOG]Warning: fb3DS v1.1-beta ($[FIRMSIG] sig) installed to $[FIRM].\n"
            elif sha $[FORPATH]@0:100 12EBA2DDB6B5203E66CBE82A963B56AECF540814F15F8539D0CE65DAE818BBB7
                set FIRM_LOG "$[FIRM_LOG]Warning: fb3DS v1.0 ($[FIRMSIG] sig) installed to $[FIRM].\n"
            else
                set FIRM_LOG "$[FIRM_LOG]Warning: Valid unknown firm with $[FIRMSIG] sig installed to $[FIRM].\n"
            end
        else
            set FIRM_LOG "$[FIRM_LOG]Information: Valid stock/unknown firm installed to $[FIRM].\n"
        end
    else 
        set FIRM_LOG "$[FIRM_LOG]Error: Invalid firm installed to $[FIRM].\n"
    end
next

@NAND_End
if chk $[FULL] "1"
    goto SD_Files
else
    goto Misc_Files
end


@SD_Files
if not isdir 0:
    set SD_LOG "$[SD_LOG]Bruh Moment: No SD card is inserted. You went out of your way to find this, didn't you?\n"
    goto SD_End
end
if isdir "0:/Nintendo 3DS"
    if isdir A:
        if find A:/dbs/title.db TITLEDB
            if shaget $[TITLEDB]@0:400 NULL
                fget $[TITLEDB]@100:4 DIFF
                #check whether SD title.db has the DIFF magic header
                if chk -u $[DIFF] "44494646"
                    if ask "The SD title.db is invalid.\nPress (A) to reset it.\n \n(This will delete all of your games and apps,\nbut they were likely also corrupted\nby whatever caused this.)"
                        rm $[TITLEDB]
                        fdummy $[TITLEDB] 400
                        set SD_LOG "$[SD_LOG]Warning: The SD title.db needs to be reset. Reboot and go into System Settings -> Data Management -> Nintendo 3DS -> Software to do this.\n"
                    else
                        set SD_LOG "$[SD_LOG]Critical: SD title.db data is invalid.\n"
                    end
                end
            else
                if ask "The SD title.db is invalid.\nPress (A) to reset it.\n \n(This will delete all of your games and apps,\nbut they were likely also corrupted\nby whatever caused this.)"
                    rm $[TITLEDB]
                    fdummy $[TITLEDB] 400
                    set SD_LOG "$[SD_LOG]Warning: The SD title.db needs to be reset. Reboot and go into System Settings -> Data Management -> Nintendo 3DS -> Software to do this.\n"
                else
                    set SD_LOG "$[SD_LOG]Critical: SD title.db is an invalid size.\n"
                end
            end 
        else
            set TITLEDB A:/dbs/title.db
            if ask "The SD title.db does not exist.\nPress (A) to create a blank one.\n \n(A title database is necessary\nto install games and apps.)"
                if not isdir A:/dbs
                    mkdir A:/dbs
                end
                fdummy $[TITLEDB] 400
                set SD_LOG "$[SD_LOG]Warning: The SD title.db needs to be reset. Reboot and go into System Settings -> Data Management -> Nintendo 3DS -> Software to do this.\n"
            else
                set SD_LOG "$[SD_LOG]Critical: SD title.db not found.\n"
            end
        end
    else
        set SD_LOG "$[SD_LOG]Warning: Nintendo 3DS folder's data is inaccessible.\n"
    end
    if not find 0:/boot.3dsx NULL
        set SD_LOG "$[SD_LOG]Warning: There is no boot.3dsx in the SD card root.\n"
    end
    if not find 0:/boot.firm NULL
        set SD_LOG "$[SD_LOG]Warning: There is no boot.firm in the SD card root.\n"
    end
else
    set SD_LOG "$[SD_LOG]Warning: Nintendo 3DS folder not found.\n"
end


@Misc_Files
# check whether the NVRAM SPI flash works, because it's bad news if it doesn't
if not shaget M:/nvram.mem@0:400 NULL
    set RAM_LOG "$[RAM_LOG]Critical: NVRAM is inaccessible.\n"
end


@Results
dumptxt 0:/gm9/ctrcheck_latest.txt "Date and Time: $[DATESTAMP] $[TIMESTAMP]\n---"
if chk -u $[NANDSECTORS_LOG] ""
    dumptxt -p 0:/gm9/ctrcheck_latest.txt $[NANDSECTORS_LOG]
end
if chk -u $[ESSENTIALS_LOG] ""
    dumptxt -p 0:/gm9/ctrcheck_latest.txt $[ESSENTIALS_LOG]
end
if chk -u $[CTRNAND_LOG] ""
    dumptxt -p 0:/gm9/ctrcheck_latest.txt $[CTRNAND_LOG]
end
if chk -u $[TWLNAND_LOG] ""
    dumptxt -p 0:/gm9/ctrcheck_latest.txt $[TWLNAND_LOG]
end
if chk -u $[FIRM_LOG] ""
    dumptxt -p 0:/gm9/ctrcheck_latest.txt $[FIRM_LOG]
end
if chk -u $[SD_LOG] ""
    dumptxt -p 0:/gm9/ctrcheck_latest.txt $[SD_LOG]
end
if chk -u $[RAM_LOG] ""
    dumptxt -p 0:/gm9/ctrcheck_latest.txt $[RAM_LOG]
end
textview 0:/gm9/ctrcheck_latest.txt
if chk $[LOG] "activated"
    dumptxt -p 0:/gm9/ctrcheck_log.txt "Date and Time: $[DATESTAMP] $[TIMESTAMP]\n---"
    if chk -u $[NANDSECTORS_LOG] ""
        dumptxt -p 0:/gm9/ctrcheck_log.txt $[NANDSECTORS_LOG]
    end
    if chk -u $[ESSENTIALS_LOG] ""
        dumptxt -p 0:/gm9/ctrcheck_log.txt $[ESSENTIALS_LOG]
    end
    if chk -u $[CTRNAND_LOG] ""
        dumptxt -p 0:/gm9/ctrcheck_log.txt $[CTRNAND_LOG]
    end
    if chk -u $[TWLNAND_LOG] ""
        dumptxt -p 0:/gm9/ctrcheck_log.txt $[TWLNAND_LOG]
    end
    if chk -u $[FIRM_LOG] ""
        dumptxt -p 0:/gm9/ctrcheck_log.txt $[FIRM_LOG]
    end
    if chk -u $[SD_LOG] ""
        dumptxt -p 0:/gm9/ctrcheck_log.txt $[SD_LOG]
    end
    if chk -u $[RAM_LOG] ""
        dumptxt -p 0:/gm9/ctrcheck_log.txt $[RAM_LOG]
    end
    echo "Check complete.\n \nThese results are also in 0:/gm9/ctrcheck_latest.txt,\nbut the file will be overwritten if you rerun this.\n \nHowever, they have also been appended to\nthe permanent log in 0:/gm9/ctrcheck_log.txt."
else
    echo "Check complete.\n \nThese results are also in 0:/gm9/ctrcheck_latest.txt,\nbut the file will be overwritten if you rerun this."
end
goto cleanup

@check_Toggle_permanent_log
if chk $[LOG] "disabled"
    set LOG "activated"
else
    set LOG "disabled"
end
goto menu

@check_Exit

wow, that's bizarre. i noticed and fixed that already, no reason it should have made it into the actual release
thanks tho