The T2 introduced new issues

It provided a new enclave for which an attacker may hide information, and is generally subject to the same classes of attack as any given iPhone model (in fact, since it is an older iPhone, this is likely)

There is mention of -chunklist-no-rev2-dev so I reverse engineered the V1 chunklist format here:

Chunk List V1

The machine boot flags:

Chosen:

+-o chosen  <class IOService, id 0x100000101, !registered, !matched, active, busy 0, retain 856>
| | {
| |   "boot-args" = <"chunklist-security-epoch=0 -chunklist-no-rev2-dev">
| |   "boot-uuid" = <"349C938F-9F05-44C1-8367-60194DDB1DCE">

Options:

+-o options  <class AppleEFINVRAM, id 0x1000002a1, registered, matched, active, busy 0 (0 ms), retain 13884>
    {
      "efi-backup-boot-device-data" = <02010c00d041030a0000000001010600001c0101060000000316100001000000000000000000000004012a0002000000062c0100000000000a82$
      "efi-backup-boot-device" = <"<array><dict><key>IOMatch</key><dict><key>IOProviderClass</key><string>IOMedia</string><key>IOPropertyMatch</key><dict><$
      "HW_BOOT_DATA" = <01000000097404000050221812000000000000000000000000750400005522191200000000000000000000000076040000002322120000000000000000000000007$
      "IONVRAM-SYNCNOW-PROPERTY" = <"IONVRAM-SYNCNOW-PROPERTY">
      "aht-results" = <"<dict><key>_name</key><string>spdiags_aht_value</string><key>spdiags_last_run_key</key><date>2019-11-01T17:52:22Z</date><key>spdiag$
      "fmm-mobileme-token-FMM" = <REDACTED>
      "bluetoothInternalControllerInfo" = <8500ac0500000000a483e75450c7>
      "fmm-mobileme-token-FMM-BridgeHasAccount" = <"BridgeHasAccountValue">
      "prev-lang:kbd" = <"en:0">
      "bluetoothActiveControllerInfo" = <8500ac05000000000000a483e75450c7>
      "fmm-computer-name" = <"Rick’s MacBook Air">
      "efi-boot-device-data" = <02010c00d041030a0000000001010600001c0101060000000316100001000000000000000000000004012a0002000000062c0100000000000a824607000$
      "backlight-level" = <7f00>
      "efi-boot-device" = <"<array><dict><key>IOMatch</key><dict><key>IOProviderClass</key><string>IOMedia</string><key>IOPropertyMatch</key><dict><key>UUI$
      "LocationServicesEnabled" = <01>
    }

The T2 boot flags:

| |   {
| |     "last-boot-args-script-vers" = <04000000>
| |     "oblit-begins" = <"OblitType: ObliterationMarkAndReboot. No reason given.">
| |     "obliteration" = <"main: NVRAM variable autoboot-oblit not detected.">
| |     "com.apple.System.rtc-offset" = <"0x2ed0a103a1b5">
| |     "boot-args" = "debug=0x104c0c"
| |     "auto-boot" = <"true">
| |     "com.apple.System.tz0-size" = <"0x1000000">
| |   }