./a.bh
Trying bytes: 1
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 2
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 3
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 4
gpg: [don't know]: indeterminate length for invalid packet type 4
Trying bytes: 5
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 6
gpg: packet(6) with unknown version 125
Trying bytes: 7

........................
Trying bytes: 21
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 22
gpg: [don't know]: indeterminate length for invalid packet type 6
...........................
Trying bytes: 24
:literal data packet:
    mode ? (4), created 2823998230, name="Ux07x82Swoxe6xd9x82xd9[Cx16xbaxebxa50rxcd#x03xbd>xec*l>xbdxb2xcbx0bx01xa6g0xfeQUxa6xc0x87xdbk9xf9ox88x8drxecxfexebxb38x93Wxebxcbxd3xc4x80xf1xdax9b(x8dxa1xbbxf6xf6x9axd0:vx81xe5rFxe09Nxdaxf3x90xcdxf0.xb0xabf<x96xf2x8dxbdx8bx95x99x89:q[)x0cxf5Xxbd2x083xc1x97xb7xeex84Sxf2xcfixf1xa2x93x15xe9kIxaax9d*;x06x0ex9cx04x13x87x88uxe7]U]xbcxb2x92x91x02;9px95x081xe9vxa5xc3x7e+#Zxb9xb8Kax18x96x82Kxaf6xb0fxb8x8d0x17xe2Dxc3&xe5xd9x94xadx05,Lxb7xccxfbx7c",
    raw data: 35666 bytes
gpg: invalid marker packet
Trying bytes: 25
gpg: unknown S2K 85
gpg: invalid symkey encrypted packet
gpg: [don't know]: invalid packet (ctb=3e)
Trying bytes: 26
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 27
..................
Trying bytes: 43
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 44
--- on this line I get the password for the prompt and I simply press enter
:encrypted data packet:
    length: 12402
gpg: assuming IDEA encrypted data
gpg: packet(3) with unknown version 94
gpg: WARNING: message was not integrity protected
gpg: [don't know]: invalid packet (ctb=22)
Trying bytes: 45
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
Trying bytes: 46
.........................
Trying bytes: 58
:literal data packet:
    mode ? (1), created 2797635547, name="g0xfeQUx00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00x00",
    raw data: 0 bytes
gpg: [don't know]: invalid packet (ctb=6b)
..........
//I get the password prompt again on this line
Trying bytes: 61
:encrypted data packet:
    length: 1731264081
gpg: assuming IDEA encrypted data
Enter passphrase:
:encrypted data packet:
    length: 1731264081
gpg: assuming IDEA encrypted data
gpg: encrypted_mdc packet with unknown version 235
gpg: WARNING: message was not integrity protected
:trust packet: flag=75 sigcache=00
gpg: [don't know]: invalid packet (ctb=21)
.....................
Trying bytes: 66
gpg: no valid OpenPGP data found.
gpg: processing message failed: eof
//here I get the password prompt again
Trying bytes: 67
:encrypted data packet:
    length: 3230129003
gpg: assuming IDEA encrypted data
gpg: encrypted_mdc packet with unknown version 180
gpg: WARNING: message was not integrity protected
gpg: packet(2) with unknown version 59

for i in {1..10}; do echo "Trying bytes: ${i}"; tail -c "+${i}" garbled.pgp | gpg --list-packets; done

tail -c +42 garbled.pgp > fixed.pgp